CVE-2026-31685

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).

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4d75bc2cd093bf5803edf512c099bfb220fd6459affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7d6a57411caf54df025860c9b1a82cd42d57a562affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d5603591373441fecf9951833d6d873e09320f08affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 288138418bef956f8b295751a4536c60f0e89f4aaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9eda5478746ef7dc0e4e537b5a5e4b0ca1027091affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 807d6ee15804df6f01a35c910f09612e858739a6affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 309ae3e9a51a69699ca94eac5fac5688fa562d55affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < fdce0b3590f724540795b874b4c8850c90e6b0a8affected
LinuxLinux2.6.12affected
LinuxLinux0 < 2.6.12unaffected
LinuxLinux5.10.258 <= 5.10.*unaffected
LinuxLinux5.15.209 <= 5.15.*unaffected
LinuxLinux6.1.175 <= 6.1.*unaffected
LinuxLinux6.6.136 <= 6.6.*unaffected
LinuxLinux6.12.83 <= 6.12.*unaffected
LinuxLinux6.18.24 <= 6.18.*unaffected
LinuxLinux6.19.14 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References