Answer in brief
CVE-2026-31685 records a Critical severity (CVSS 9.4) vulnerability in netfilter: ip6t_eui64: reject invalid MAC header for all packets. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). 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 9.4. 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 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4d75bc2cd093bf5803edf512c099bfb220fd6459 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7d6a57411caf54df025860c9b1a82cd42d57a562 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d5603591373441fecf9951833d6d873e09320f08 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <288138418bef956f8b295751a4536c60f0e89f4a || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9eda5478746ef7dc0e4e537b5a5e4b0ca1027091 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <807d6ee15804df6f01a35c910f09612e858739a6 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <309ae3e9a51a69699ca94eac5fac5688fa562d55 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fdce0b3590f724540795b874b4c8850c90e6b0a8 | 4d75bc2cd093bf5803edf512c099bfb220fd6459, 7d6a57411caf54df025860c9b1a82cd42d57a562, d5603591373441fecf9951833d6d873e09320f08, 288138418bef956f8b295751a4536c60f0e89f4a, 9eda5478746ef7dc0e4e537b5a5e4b0ca1027091, 807d6ee15804df6f01a35c910f09612e858739a6, 309ae3e9a51a69699ca94eac5fac5688fa562d55, fdce0b3590f724540795b874b4c8850c90e6b0a8 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
Published upstream
Apr 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 15, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6t_eui64: reject invalid MAC header for all packets `eui64_mt6()` derives a modified EUI-64 from the Ethernet source address and compares it with the low 64 bits of the IPv6 source address. The existing guard only rejects an invalid MAC header when `par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()` can still reach `eth_hdr(skb)` even when the MAC header is not valid. Fix this by removing the `par->fragoff != 0` condition so that packets with an invalid MAC header are rejected before accessing `eth_hdr(skb)`.
Quoted source text, attributed separately from HOL analysis.