CVE-2026-31685: netfilter: ip6t_eui64: reject invalid MAC header for all packets
Vulnerability summary
CVE-2026-31685 is a critical (CVSS 9.4) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 41.8% of scored vulnerabilities.
Severe, CVSS 9.4 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 175 · Related 168Showing 100 of 182.
Timeline
- 25-04-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
Description
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)`.
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.4CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
- OSV · DebianEcosystem advisory · calculated9.4CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
- OSV · ChainguardEcosystem advisory · calculated9.4CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
- NVDNIST9.4CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
EPSS trend
Probability
0.48%
Chance of exploitation in the next 30 days
Percentile
42%
Versus all other CVEs
30-day change
Decrease -0.14 pp
From 0.62% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu157 products
- linux< 3.13.0-215.266 | < 4.4.0-283.317 | < 4.15.0-253.265 | < 5.4.0-233.253 | < 5.15.0-185.195 | < 6.8.0-134.134 | < 6.17.0-40.40
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.4.0-1156.162 | < 4.4.0-1194.209 | < 4.15.0-1194.207 | < 5.4.0-1161.172 | < 5.15.0-1111.118 | < 6.8.0-1060.63 | < 6.17.0-1019.19
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Chainguard5 products
- linux-aws-6.18< 6.18.31-r0
- linux-azure-6.18< 6.18.24-r1 | < 6.18.31-r0
- linux-gcp-6.18< 6.18.31-r0
- linux-qemu-6.18< 6.18.24-r3
- linux-vmware-6.18< 6.18.31-r0
Linux2 products
- linux≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4d75bc2cd093bf5803edf512c099bfb220fd6459 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7d6a57411caf54df025860c9b1a82cd42d57a562 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < d5603591373441fecf9951833d6d873e09320f08 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 288138418bef956f8b295751a4536c60f0e89f4a | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 9eda5478746ef7dc0e4e537b5a5e4b0ca1027091 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 807d6ee15804df6f01a35c910f09612e858739a6 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 309ae3e9a51a69699ca94eac5fac5688fa562d55 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < fdce0b3590f724540795b874b4c8850c90e6b0a8 | 2.6.12
- linux_kernel≥ 2.6.12.1, < 6.6.136 | ≥ 6.7, < 6.12.83 | ≥ 6.13, < 6.18.24 | ≥ 6.19, < 6.19.14 | 2.6.12 | 2.6.12:rc2 | 2.6.12:rc3 | 2.6.12:rc4 | 2.6.12:rc5 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6 | 7.0:rc7
Debian1 product
- linux< 6.1.176-1 | < 6.12.85-1 | < 6.19.14-1
4 vendors · 165 products
