Critical severity · published Apr 25, 2026
CVE-2026-31685
netfilter: ip6t_eui64: reject invalid MAC header for all packets
9.4
CVSS
0.5%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
Low
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
2.6.12.1 before 6.6.136; 6.7 before 6.12.83; 6.13 before 6.18.24; 6.19 before 6.19.14; 2.6.12; 2.6.12; +10 more · source: NVD
LI
Linux · Linux
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 4d75bc2cd093bf5803edf512c099bfb220fd6459; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 7d6a57411caf54df025860c9b1a82cd42d57a562; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before d5603591373441fecf9951833d6d873e09320f08; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 288138418bef956f8b295751a4536c60f0e89f4a; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 9eda5478746ef7dc0e4e537b5a5e4b0ca1027091; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 807d6ee15804df6f01a35c910f09612e858739a6; +3 more · source: vendor
SS
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem · Siemens
0 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31685
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-31685
Patch
https://git.kernel.org/stable/c/288138418bef956f8b295751a4536c60f0e89f4a
Patch
https://git.kernel.org/stable/c/309ae3e9a51a69699ca94eac5fac5688fa562d55
git.kernel.org
https://git.kernel.org/stable/c/4d75bc2cd093bf5803edf512c099bfb220fd6459
git.kernel.org
https://git.kernel.org/stable/c/7d6a57411caf54df025860c9b1a82cd42d57a562
Patch
https://git.kernel.org/stable/c/807d6ee15804df6f01a35c910f09612e858739a6
Patch
https://git.kernel.org/stable/c/9eda5478746ef7dc0e4e537b5a5e4b0ca1027091
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