Answer in brief
CVE-2026-31495 records a Medium severity (CVSS 5.5) vulnerability in netfilter: ctnetlink: use netlink policy range checks. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-31495 records a Medium severity (CVSS 5.5) vulnerability in netfilter: ctnetlink: use netlink policy range checks. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <435b576cd2faa75154777868f8cbb73bf71644d3 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <2ef71307c86a9f866d6e28f1a0c06e2e9d794474 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <4f7d25f3f0786402ba48ff7d13b6241d77d975f5 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <fcec5ce2d73a41668b24e3f18c803541602a59f6 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <675c913b940488a84effdeeac5a1cfb657b59804 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <c6cb41eaae875501eaaa487b8db6539feb092292 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <45c33e79ae705b7af97e3117672b6cd258dd0b1b || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <8f15b5071b4548b0aafc03b366eb45c9c6566704 | 435b576cd2faa75154777868f8cbb73bf71644d3, 2ef71307c86a9f866d6e28f1a0c06e2e9d794474, 4f7d25f3f0786402ba48ff7d13b6241d77d975f5, fcec5ce2d73a41668b24e3f18c803541602a59f6, 675c913b940488a84effdeeac5a1cfb657b59804, c6cb41eaae875501eaaa487b8db6539feb092292, 45c33e79ae705b7af97e3117672b6cd258dd0b1b, 8f15b5071b4548b0aafc03b366eb45c9c6566704 |
| Linux/Linuxgeneric | 2.6.22 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Apr 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: use netlink policy range checks Replace manual range and mask validations with netlink policy annotations in ctnetlink code paths, so that the netlink core rejects invalid values early and can generate extack errors. - CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at policy level, removing the manual >= TCP_CONNTRACK_MAX check. - CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE (14). The normal TCP option parsing path already clamps to this value, but the ctnetlink path accepted 0-255, causing undefined behavior when used as a u32 shift count. - CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with CTA_FILTER_F_ALL, removing the manual mask checks. - CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding a new mask define grouping all valid expect flags. Extracted from a broader nf-next patch by Florian Westphal, scoped to ctnetlink for the fixes tree.
Quoted source text, attributed separately from HOL analysis.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <435b576cd2faa75154777868f8cbb73bf71644d3 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <2ef71307c86a9f866d6e28f1a0c06e2e9d794474 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <4f7d25f3f0786402ba48ff7d13b6241d77d975f5 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <fcec5ce2d73a41668b24e3f18c803541602a59f6 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <675c913b940488a84effdeeac5a1cfb657b59804 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <c6cb41eaae875501eaaa487b8db6539feb092292 || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <45c33e79ae705b7af97e3117672b6cd258dd0b1b || >=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <8f15b5071b4548b0aafc03b366eb45c9c6566704 | 435b576cd2faa75154777868f8cbb73bf71644d3, 2ef71307c86a9f866d6e28f1a0c06e2e9d794474, 4f7d25f3f0786402ba48ff7d13b6241d77d975f5, fcec5ce2d73a41668b24e3f18c803541602a59f6, 675c913b940488a84effdeeac5a1cfb657b59804, c6cb41eaae875501eaaa487b8db6539feb092292, 45c33e79ae705b7af97e3117672b6cd258dd0b1b, 8f15b5071b4548b0aafc03b366eb45c9c6566704 |
| Linux/Linuxgeneric | 2.6.22 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Apr 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: use netlink policy range checks Replace manual range and mask validations with netlink policy annotations in ctnetlink code paths, so that the netlink core rejects invalid values early and can generate extack errors. - CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at policy level, removing the manual >= TCP_CONNTRACK_MAX check. - CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE (14). The normal TCP option parsing path already clamps to this value, but the ctnetlink path accepted 0-255, causing undefined behavior when used as a u32 shift count. - CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with CTA_FILTER_F_ALL, removing the manual mask checks. - CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding a new mask define grouping all valid expect flags. Extracted from a broader nf-next patch by Florian Westphal, scoped to ctnetlink for the fixes tree.
Quoted source text, attributed separately from HOL analysis.