Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Evidence dossier
CVE-2017-1000253
CVE-2017-1000253
gen-56ccdaf9Normalized restatement
Linux distributions that have not patched their long-term kernels with https://git.kernel.org/linus/a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (committed on April 14, 2015). This kernel vulnerability was fixed in April 2015 by commit a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (backported to Linux 3.10.77 in May 2015), but it was not recognized as a security threat. With CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE enabled, and a normal top-down address allocation strategy, load_elf_binary() will attempt to map a PIE binary into an address range immediately below mm->mmap_base. Unfortunately, load_elf_ binary() does not take account of the need to allocate sufficient space for the entire binary which means that, while the first PT_LOAD segment is mapped below mm->mmap_base, the subsequent PT_LOAD segment(s) end up being mapped above mm->mmap_base into the are that is supposed to be the "gap" between the stack and the binary.
- State
- PUBLISHED
- Published
- Oct 4, 2017
- Updated
- Oct 21, 2025
- Evidence coverage
- 85%
2026-07-18 · v2026.06.15 · percentile 95.3%
Distinct CVSS assessments remain side by side; none are averaged.
Source comparison
Who said what
Linux distributions that have not patched their long-term kernels with https://git.kernel.org/linus/a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (committed on April 14, 2015). This kernel vulnerability was fixed in April 2015 by commit a87938b2e246b81b4fb713edb371a9fa3c5c3c86 (backported to Linux 3.10.77 in May 2015), but it was not recognized as a security threat. With CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE enabled, and a normal top-down address allocation strategy, load_elf_binary() will attempt to map a PIE binary into an address range immediately below mm->mmap_base. Unfortunately, load_elf_ binary() does not take account of the need to allocate sufficient space for the entire binary which means that, while the first PT_LOAD segment is mapped below mm->mmap_base, the subsequent PT_LOAD segment(s) end up being mapped above mm->mmap_base into the are that is supposed to be the "gap" between the stack and the binary.
Linux Kernel PIE Stack Buffer Corruption Vulnerability
Probability 0.106950000000; percentile 0.953200000000
Applicability
Cited product scope
[{"status": "affected", "version": "6.0"}]unknown[{"status": "affected", "version": "6.1"}]unknown[{"status": "affected", "version": "6.2"}]unknown[{"status": "affected", "version": "6.3"}]unknown[{"status": "affected", "version": "6.4"}]unknown[{"status": "affected", "version": "6.5"}]unknown[{"status": "affected", "version": "6.6"}]unknown[{"status": "affected", "version": "6.7"}]unknown[{"status": "affected", "version": "6.8"}]unknown[{"status": "affected", "version": "6.9"}]unknown[{"status": "affected", "version": "7.1406"}]unknown[{"status": "affected", "version": "7.1503"}]unknown[{"status": "affected", "version": "7.1511"}]unknown[{"status": "affected", "version": "7.1611"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "2.6.25", "lessThan": "3.2.70", "versionType": "custom"}, {"status": "affected", "version": "3.3", "lessThan": "3.4.109", "versionType": "custom"}, {"status": "affected", "version": "3.5", "lessThan": "3.10.77", "versionType": "custom"}, {"status": "affected", "version": "3.11", "lessThan": "3.12.43", "versionType": "custom"}, {"status": "affected", "version": "3.13", "lessThan": "3.14.41", "versionType": "custom"}, {"status": "affected", "version": "3.15", "lessThan": "3.16.35", "versionType": "custom"}, {"status": "affected", "version": "3.17", "lessThan": "3.18.14", "versionType": "custom"}, {"status": "affected", "version": "3.19", "lessThan": "3.19.7", "versionType": "custom"}, {"status": "affected", "version": "1.0", "lessThan": "4.0.2", "versionType": "custom"}]unknown[{"status": "affected", "version": "n/a"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknown[{"status": "affected", "version": "6.0"}, {"status": "affected", "version": "6.1"}, {"status": "affected", "version": "6.2"}, {"status": "affected", "version": "6.3"}, {"status": "affected", "version": "6.4"}, {"status": "affected", "version": "6.5"}, {"status": "affected", "version": "6.6"}, {"status": "affected", "version": "6.7"}, {"status": "affected", "version": "6.8"}, {"status": "affected", "version": "6.9"}, {"status": "affected", "version": "7.0"}, {"status": "affected", "version": "7.1"}, {"status": "affected", "version": "7.2"}, {"status": "affected", "version": "7.3"}]unknowncpe:2.3:o:centos:centos:6.0:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.1:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.2:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.3:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.4:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.5:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.6:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.7:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.8:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:6.9:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:7.1406:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:7.1503:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:7.1511:*:*:*:*:*:*:*supportedcpe:2.3:o:centos:centos:7.1611:*:*:*:*:*:*:*supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 2.6.25; end excluding 3.2.70supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.3; end excluding 3.4.109supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.5; end excluding 3.10.77supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.11; end excluding 3.12.43supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.13; end excluding 3.14.41supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.15; end excluding 3.16.35supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.17; end excluding 3.18.14supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 3.19; end excluding 3.19.7supportedcpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*; start including 4.0; end excluding 4.0.2supportedcpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.1:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.2:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.3:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.4:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.5:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.6:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.7:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.8:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:6.9:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:7.1:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:7.2:*:*:*:*:*:*:*supportedcpe:2.3:o:redhat:enterprise_linux:7.3:*:*:*:*:*:*:*supportedAssessments
CVSS by origin
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HAV:L/AC:L/Au:N/C:C/I:C/A:CCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLimitations and unknowns
- KEV membership is authoritative for the catalog, not proof of exposure in any environment.
- EPSS is a dated model probability and not an individual-environment prediction.
- Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
- NVD-carried upstream facts remain derivative and are not independent corroboration.
- Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
- NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
- Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
- Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.