CASCACascade Atlas

Evidence dossier

CVE-2025-39964

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg

Exploited in the wild (CISA KEV since Sep 18, 2026). NVD reports CVSS 3.1 5.5. Severity assessments differ within at least one CVSS version. EPSS estimates 1.4% exploit likelihood as of Oct 22, 2026.

56.1–74.0Priority evidence range
Evidence through Oct 22, 2026, 6:07 PM UTC

As of Oct 22, 2026

Normalized restatement

In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg Issuing two writes to the same af_alg socket is bogus as the data will be interleaved in an unpredictable fashion. Furthermore, concurrent writes may create inconsistencies in the internal socket state. Disallow this by adding a new ctx->write field that indiciates exclusive ownership for writing.

State
PUBLISHED
Published
Oct 13, 2025
Updated
Oct 15, 2026
Evidence coverage
72%

Evidence chronology

What was known when

Download this view's receipt →
  1. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Linux Kernel Race Condition Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Linux Kernel Race Condition Vulnerability
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    CISA-ADP

    Record text: CISA ADP Vulnrichment

    Inspect raw assertion
    Field
    container
    Value
    CISA ADP Vulnrichment
    Original evidence ↗
  3. Source dateSource date omittedFirst observed by CASCA
    Linux

    Record text: crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg

    Inspect raw assertion
    Field
    container
    Value
    crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg
    Original evidence ↗
  4. Source dateSource date omittedFirst observed by CASCA
    siemens-SADP

    Record text: Container present

    Inspect raw assertion
    Field
    container
    Value
    Container present
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 1.36% probability · 71.55th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.013620000000; percentile 0.715500000000
    Original evidence ↗

Assessments differ

NVD5.5CVSS 3.1 · source date omitted
CVE Program source7.8CVSS 3.1 · source date omitted

Values are shown separately by source and CVSS version.

ExploitationCatalog member

CISA KEV · catalog date Sep 18, 2026 · first observed Sep 18, 2026

Exploit likelihood1.36%

FIRST EPSS · score date Oct 22, 2026 · 71.6th percentile · first observed Oct 22, 2026

SeverityAssessments differ

NVD · CVSS 3.1 · first observed Oct 21, 2026 · values shown separately below

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusLast verified source snapshot retained

The last verified source boundary remains in force for this claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
Review source contract
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
None
Severity assessmentAssessments differ

Eligible assertions materially conflict and remain visible side by side.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Oct 22, 2026
Resolution
Resolve conflict
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Oct 22, 2026
Resolution
Resolve identity

Source comparison

Who said what

CISA KEVOriginal assertion
Exploitation cataloged

Linux Kernel Race Condition Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Linux Kernel Race Condition Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
CISA-ADPIndependent enrichment
Record text

CISA ADP Vulnrichment

Inspect raw assertion
Field
container
Value
CISA ADP Vulnrichment
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
LinuxOriginal assertion
Record text

crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg

Inspect raw assertion
Field
container
Value
crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
siemens-SADPSource-declared origin
Record text

Container present

Inspect raw assertion
Field
container
Value
Container present
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

1.36% probability · 71.55th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.013620000000; percentile 0.715500000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
12Underlying assertions
1Canonical products
12Target assertions
0Constraint assertions

Grouped from 1 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.

Identity source boundaries
  • Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z27d65b0f-b718-4b4f-bb79-c47c68d09dfa
  • Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z955dae73-7302-438b-aee1-058d7cc5d48e

13 scope groups

Linux · source assertedLinuxLinuxDirect source scope
Affected: 2.6.38Unaffected: 0 to before 2.6.38 (semver comparison)Unaffected: 5.10.245 through 5.10.* (semver comparison)Unaffected: 5.15.194 through 5.15.* (semver comparison)Unaffected: 6.1.154 through 6.1.* (semver comparison)Unaffected: 6.6.108 through 6.6.* (semver comparison)Unaffected: 6.12.49 through 6.12.* (semver comparison)Unaffected: 6.16.9 through 6.16.* (semver comparison)Unaffected: 6.17 through * (original_commit_for_fix comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "2.6.38"}, {"status": "unaffected", "version": "0", "lessThan": "2.6.38", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.245", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.194", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.154", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.108", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.49", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.16.9", "versionType": "semver", "lessThanOrEqual": "6.16.*"}, {"status": "unaffected", "version": "6.17", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}]
Linux · source assertedLinuxLinuxDirect source scope
Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before 0f28c4adbc4a97437874c9b669fd7958a8c6d6ce (git comparison)Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before e4c1ec11132ec466f7362a95f36a506ce4dc08c9 (git comparison)Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8 (git comparison)Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before 7c4491b5644e3a3708f3dbd7591be0a570135b84 (git comparison)Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before 9aee87da5572b3a14075f501752e209801160d3d (git comparison)Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before 45bcf60fe49b37daab1acee57b27211ad1574042 (git comparison)Affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to before 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 (git comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "0f28c4adbc4a97437874c9b669fd7958a8c6d6ce", "versionType": "git"}, {"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "e4c1ec11132ec466f7362a95f36a506ce4dc08c9", "versionType": "git"}, {"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8", "versionType": "git"}, {"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "7c4491b5644e3a3708f3dbd7591be0a570135b84", "versionType": "git"}, {"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "9aee87da5572b3a14075f501752e209801160d3d", "versionType": "git"}, {"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "45bcf60fe49b37daab1acee57b27211ad1574042", "versionType": "git"}, {"status": "affected", "version": "8ff590903d5fc7f5a0a988c38267a3d08e6393a2", "lessThan": "1b34cbbf4f011a121ef7b2d7d6e6920a036d5285", "versionType": "git"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPDirect source scope
Affected: V3.1.6 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPDirect source scope
Affected: V3.1.7 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.7", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPDirect source scope
Affected: V3.1.6 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPDirect source scope
Affected: V3.1.7 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.7", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPDirect source scope
Affected: V3.1.6 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPDirect source scope
Affected: V3.1.7 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.7", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPDirect source scope
Affected: V3.1.7 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.7", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPDirect source scope
Affected: V3.1.6 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPDirect source scope
Affected: V3.1.6 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom"}]
siemens-SADP · source assertedSiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPDirect source scope
Affected: V3.1.7 to before * (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "V3.1.7", "lessThan": "*", "versionType": "custom"}]
NVD CPE · OPERATING SYSTEMlinuxlinux_kernelVulnerable target · 12 assertions
Any version (unconstrained) (>= 2.6.38, < 5.10.245); Any version (unconstrained) (>= 5.11, < 5.15.194); Any version (unconstrained) (>= 5.16, < 6.1.154); Any version (unconstrained) (>= 6.13, < 6.16.9); Any version (unconstrained) (>= 6.2, < 6.6.108); Any version (unconstrained) (>= 6.7, < 6.12.49); Version 6.17Canonical identity product-0eda7a801761be4590f267cf319481c8c0aaa30546d99cc064edf77989ce05c9Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 6
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    327d22ef-390b-454c-bd31-2ed23c998a1c
  2. cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    from including 2.6.38; through excluding 5.10.245
    Match ID
    ec314bad-d810-4c02-abb3-11d90e06aeaa
  3. cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 10
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    47e4c5c0-079f-4838-971b-8c503d48fcc2
  4. cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    from including 5.16; through excluding 6.1.154
    Match ID
    e49cd91e-fc55-45b0-bb63-9ad5f5d70caa
  5. cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 11
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    5a4516a6-c12e-42a4-8c0e-68aef3264504
  6. cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    from including 5.11; through excluding 5.15.194
    Match ID
    cf862263-dc8d-4324-a52a-da1d7880b35a
  7. cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    from including 6.2; through excluding 6.6.108
    Match ID
    a7e8eaee-7731-4996-9578-696255d61ea2
  8. cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 8
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    39982c4b-716e-4b2f-8196-fa301f47807d
  9. cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 4
    Logic
    OR
    Version bounds
    from including 6.7; through excluding 6.12.49
    Match ID
    caa033e9-a2c5-4976-a83e-9804d8fb827f
  10. cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 9
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    340beea9-d70d-4290-b502-fbb1032353b1
  11. cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 7
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    c730cd9a-d969-4a8e-9522-162aaf7c0ee9
  12. cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 5
    Logic
    OR
    Version bounds
    from including 6.13; through excluding 6.16.9
    Match ID
    638dd910-1189-4f5e-98bf-2d436b695112

Affected-product evidence

Accepted scope and product mapping

0 canonical links · 2 source-reported links

Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Direct cve affected
Assertions
12
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
1b6c5f40-7ee7-4cca-b3c5-123f2ee729541cf23d70-f18b-42fc-bf05-c7a02f3b73e322b14251-6ab1-49c9-b2e2-e1909aaa696435b8216c-5e6b-4b69-8574-c5ad1627d76d3c126c4b-9559-4199-901a-65bb2db69dc6437a3f32-8d92-482a-95f4-ff72da6eebb86a57520a-a268-47a5-8d2f-1dd321eca98f82d19395-f2da-4ac2-8635-047fc7a135f0a30badcd-5172-4e67-9dbf-7d28cc2de270b2e913ec-d2f1-465e-a681-9a6d62466356f66fc480-c398-4ce8-87b5-91eb01597c27f7b75b4f-54d0-4c02-8c72-d2435ca2414a
Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Nvd cpe vulnerable target
Assertions
14
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
26808772-a105-487c-89fc-dc41f7ce24b92b4c839b-36b7-481f-be4c-9ca391c3bd46426a4671-8b79-40ce-be77-7421ff07c8dd42ff8df2-5fa3-4859-8e6b-8d7ff17d3c5f58448396-1d34-4622-8ff1-60fe18c9e9c36cda03da-2052-4a67-91bf-407596aa077870710ef4-e9b6-4969-8972-3d6783f24477739e6850-d8ca-40a7-9665-676b10396ffd7a12ba88-8bdf-45c9-9a7d-eba8799522478e96958d-255b-4bad-8850-33a54d8c12ee9bfb1544-7be2-483a-a1cb-1c11d649a055a61ba1d1-defc-4ac8-be9a-744b9d67f7c6a89c83c1-7327-4c70-8ae9-343953d017afb2224f08-1838-45cc-a043-2f49cd26c052

Assessments

CVSS by origin

5.5
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8
CVE Program sourceCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8
LinuxCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Direct CVE/CNA normalized decisions

7.8Priority eligible

Linux

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Validation
Valid match
Recomputed
7.8
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1

Assessments are retained side by side under closed precedence. Cascade never averages CVSS.

Evidence boundaries

  • 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; remaining scope stays source-scoped.
  • NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
  • 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.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
  • OSV aggregation and OSV-converted NVD material are not independent corroboration.
  • Red Hat facts are vendor assertions for the exact supplied products.
  • Nonmembership and not-yet-observed states are not proof of safety.