netfilter: ip6t_eui64: reject invalid MAC header for all packets

Summary

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)`.

Timeline

1. Apr 25, 2026, 8:47 AM UTCCVE published
2. Oct 16, 2026, 3:12 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Oct 19, 2026, 6:56 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 4d75bc2cd093bf5803edf512c099bfb220fd6459; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 7d6a57411caf54df025860c9b1a82cd42d57a562; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in d5603591373441fecf9951833d6d873e09320f08; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 288138418bef956f8b295751a4536c60f0e89f4a; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 9eda5478746ef7dc0e4e537b5a5e4b0ca1027091; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 807d6ee15804df6f01a35c910f09612e858739a6; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 309ae3e9a51a69699ca94eac5fac5688fa562d55; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in fdce0b3590f724540795b874b4c8850c90e6b0a8

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.136; From 6.7.0 · fixed in 6.12.83; From 6.13.0 · fixed in 6.18.24; From 6.19.0 · fixed in 6.19.14

References 8