CISA KEV · catalog date Nov 3, 2021 · first observed Jul 19, 2026
Evidence dossier
CVE-2017-8759
Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or application, aka ".NET…
Exploited in the wild (CISA KEV since Nov 3, 2021). NVD reports CVSS 3.1 7.8. EPSS estimates 88.7% exploit likelihood as of Aug 27, 2026.
As of Aug 27, 2026
Normalized restatement
Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or application, aka ".NET Framework Remote Code Execution Vulnerability."
- State
- PUBLISHED
- Published
- Sep 13, 2017
- Updated
- Oct 21, 2025
- Evidence coverage
- 98%
Evidence chronology
What was known when
- Source dateSource date omittedFirst observed by CASCACISA-ADPOriginal evidence ↗
Record text: CISA ADP Vulnrichment
Inspect raw assertion
- Field
container- Value
- CISA ADP Vulnrichment
- Source dateSource date omittedFirst observed by CASCACVE ProgramOriginal evidence ↗
Record text: CVE Program Container
Inspect raw assertion
- Field
container- Value
- CVE Program Container
- Source dateSource date omittedFirst observed by CASCAmicrosoftOriginal evidence ↗
Record text: Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or application, aka ".NET Framework Remote Code Execution Vulnerability."
Inspect raw assertion
- Field
container- Value
- Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or application, aka ".NET Framework Remote Code Execution Vulnerability."
- Source dateFirst observed by CASCACISA KEVOriginal evidence ↗
Exploitation cataloged: Microsoft .NET Framework Remote Code Execution Vulnerability
Inspect raw assertion
- Field
observed_exploitation- Value
- Microsoft .NET Framework Remote Code Execution Vulnerability
- Source dateFirst observed by CASCAFIRST EPSSOriginal evidence ↗
EPSS score: 88.7% probability · 99.76th percentile
Inspect raw assertion
- Field
model_probability- Value
- Probability 0.886980000000; percentile 0.997630000000
FIRST EPSS · score date Aug 27, 2026 · 99.8th percentile · first observed Aug 27, 2026
NVD · CVSS 3.1 · first observed Jul 19, 2026 · same-version scores align in this snapshot
Evidence detail
Source limits and decisions
Why each evidence state has this value
casca-unknown-reasons-v1Eligible evidence is present for this bounded claim.
- Revision
- evidence-policy-v1.1.0
- Cutoff
- Aug 27, 2026
- Resolution
- None
Eligible evidence is present for this bounded claim.
- Revision
- evidence-policy-v1.1.0
- Cutoff
- Aug 27, 2026
- Resolution
- None
Eligible evidence is present for this bounded claim.
- Revision
- casca-direct-cvss-eligibility-v1
- Cutoff
- Aug 27, 2026
- Resolution
- None
The cited source assertion is retained while canonical product linkage remains open.
- Revision
- casca-factor-d-obligations-v1
- Cutoff
- Aug 27, 2026
- Resolution
- Resolve identity
Source comparison
Who said what
CISA ADP Vulnrichment
Inspect raw assertion
- Field
container- Value
- CISA ADP Vulnrichment
CVE Program Container
Inspect raw assertion
- Field
container- Value
- CVE Program Container
Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or application, aka ".NET Framework Remote Code Execution Vulnerability."
Inspect raw assertion
- Field
container- Value
- Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to execute code remotely via a malicious document or application, aka ".NET Framework Remote Code Execution Vulnerability."
Microsoft .NET Framework Remote Code Execution Vulnerability
Inspect raw assertion
- Field
observed_exploitation- Value
- Microsoft .NET Framework Remote Code Execution Vulnerability
88.7% probability · 99.76th percentile
Inspect raw assertion
- Field
model_probability- Value
- Probability 0.886980000000; percentile 0.997630000000
Applicability
Cited product scope
Grouped from 18 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 2026-07-21T06:45:29.809Z
27d65b0f-b718-4b4f-bb79-c47c68d09dfa - Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z
955dae73-7302-438b-aee1-058d7cc5d48e
12 scope groups
Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7"}]product-c3f13a19428f1ba85d60b6a58ac8c4637007c76c19683b493bea98fadd835759Linked exactInspect raw assertions
cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 7 · node/0 · match 3
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
734112b3-1383-4be3-8721-c0f84566b764
cpe:2.3:a:microsoft:.net_framework:4.6:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 5 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
280fe663-23be-45d2-9b31-5f577e390b48
cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 3 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
42a6df09-b8e1-414d-97e7-453566055279
cpe:2.3:a:microsoft:.net_framework:4.5.2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
40b3a045-b08a-44e0-91be-726753f6a362
cpe:2.3:a:microsoft:.net_framework:4.6:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 7 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
280fe663-23be-45d2-9b31-5f577e390b48
cpe:2.3:a:microsoft:.net_framework:3.5.1:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 1 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
8edc4407-7e92-4e60-82f0-0c87d1860d3a
cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 8 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
a16ad2b0-2189-4e8e-b7fc-ce598ca1cb2d
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 2 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
23317443-1968-4791-9f20-ad3b308a83d1
cpe:2.3:a:microsoft:.net_framework:4.6.1:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 4 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
ff0b660d-1f30-4d45-b98b-726edb8cb90f
cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 7 · node/0 · match 2
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
a16ad2b0-2189-4e8e-b7fc-ce598ca1cb2d
cpe:2.3:a:microsoft:.net_framework:4.6.1:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 7 · node/0 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
ff0b660d-1f30-4d45-b98b-726edb8cb90f
cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 6 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
734112b3-1383-4be3-8721-c0f84566b764
cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 8 · node/0 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
734112b3-1383-4be3-8721-c0f84566b764
product-9851bd571b8ab08bca589cd73710badfef557d036f0fb7707f694f1c9f597cb4Linked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_10_1507:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
542daeec-73cc-46c6-a630-bf474a3446ac
cpe:2.3:o:microsoft:windows_10_1507:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 5 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
542daeec-73cc-46c6-a630-bf474a3446ac
product-7b807aecec9e7ce1999b1cdf357022e504d2f3daa554142c46b57e2c37e3597aLinked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_10_1511:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 4 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
7a8e9d99-bd78-4340-88f2-5aff27ac37c9
cpe:2.3:o:microsoft:windows_10_1511:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
7a8e9d99-bd78-4340-88f2-5aff27ac37c9
product-740fec3e9838b5eabe76ebe27e4d0d7a4cb2e0ef7e13923300d3d0b51e3fce1cLinked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 8 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
61019899-d7af-46e4-a72c-d189180f66ab
cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 2
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
61019899-d7af-46e4-a72c-d189180f66ab
product-2f3550a8fd2528ab6e756c5ea638f5f3dc368adee47ca6f01d64918c0b9eb2a5Linked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_10_1703:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 3
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
e1dd582c-1660-4e6e-81a1-537bd1307a99
cpe:2.3:o:microsoft:windows_10_1703:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 6 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
e1dd582c-1660-4e6e-81a1-537bd1307a99
product-f20a05098a41a238f96b56b817d0482887bb39ad40620198bbe05da10ee02ffcLinked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c2b1c231-de19-4b8f-a4aa-5b3a65276e46
cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 7 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c2b1c231-de19-4b8f-a4aa-5b3a65276e46
cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c2b1c231-de19-4b8f-a4aa-5b3a65276e46
product-7e46de82012029583622f69d79b86bc210b5bd25b8cb3bb4468936702b23c4b0Linked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 4
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
e93068db-549b-45ab-8e5c-00eb5d8b5cf8
cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
e93068db-549b-45ab-8e5c-00eb5d8b5cf8
product-076c7e47c78d9425d54dea0b063ed7cd79e5f9f0bfdb3c9153b8aec4e71a7ad9Linked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 7 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c6ce5198-c498-4672-af4c-77ab4be06c5c
cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 2
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c6ce5198-c498-4672-af4c-77ab4be06c5c
product-217b1ab3d25f361a639824f86753d418b35aa2a816ee370bb71b5d1dd883d87aLinked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 5 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
5f422a8c-2c4e-42c8-b420-e0728037e15c
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 7 · node/1 · match 2
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
af07a81d-12e5-4b1d-bff9-c8d08c32ff4f
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
2aca9287-b475-4af7-a4da-a7143cef9e57
cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 3 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
66cafdb7-9d41-4e67-ab83-5eb104551ff5
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 3
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
5f422a8c-2c4e-42c8-b420-e0728037e15c
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 4
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
af07a81d-12e5-4b1d-bff9-c8d08c32ff4f
product-5a80416e92fed0cddbb3d4f3840218b448dee11159824ad25a0353da566963feLinked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 7 · node/1 · match 3
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
a7df96f8-ba6a-4780-9ca3-f719b3f81074
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 5
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
a7df96f8-ba6a-4780-9ca3-f719b3f81074
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 6
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
db18c4ce-5917-401e-acf7-2747084fd36e
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 7 · node/1 · match 4
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
db18c4ce-5917-401e-acf7-2747084fd36e
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 5
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
a7df96f8-ba6a-4780-9ca3-f719b3f81074
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 6
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
db18c4ce-5917-401e-acf7-2747084fd36e
product-02e254d111ce604757a15650ef469f4f8365d6247da82ce3ac2695c3cfc7dc5fLinked exactInspect raw assertions
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 8 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
041ff8ba-0b12-4a1f-b4bf-9c4f33b7c1e7
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 7
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
041ff8ba-0b12-4a1f-b4bf-9c4f33b7c1e7
Affected-product evidence
Accepted scope and product mapping
1 canonical links · 1 source-reported links
vendor-01299a5a765aea70faa05f2d06e0c26a5d498fd34553e868d89e8a43b31864db · product-c3f13a19428f1ba85d60b6a58ac8c4637007c76c19683b493bea98fadd835759
- Source class
- Nvd cpe vulnerable target
- Assertions
- 13
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
04e14c1f-0050-41eb-96f2-af2a2ea8dc0f086afe5d-660f-47b6-825c-6edd0a17787e0be49d55-8275-4733-9592-d311b80346300dda5b43-ad92-4e37-91bc-480496a63bbc435567b3-a007-425e-ab00-952ee27109d77756f4ee-54dd-484f-847a-7e447fe3e56f993722c9-1023-4d6c-b300-682cd04cb29a9f3040fd-13f6-4903-a170-28da08d7d378b456273c-1d2f-4110-a832-d493def9159fc04b798e-b888-4c01-a6fb-e87fd9637cc6d3bf38ca-15f9-48cf-9f7b-694689dc7128ee68ff7b-f333-46ff-aa03-91509cc82a35f8dd1f4d-fb5d-4257-abd3-85366a4b9a5eCanonical 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
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
05846f77-6b1c-452a-be05-29b748ef4ceaAssessments
CVSS by origin
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HAV:N/AC:M/Au:N/C:C/I:C/A:CCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HDirect CVE/CNA normalized decisions
CISA-ADP
CVSS 3.1 · Secondary · Independent enrichment · rank 2
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.