CVE-2026-31685
Full vulnerability record from the local CVENow database.
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)`.
Severity
CRITICAL
CVSS score
9.4
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-04-25 09:16:02.273000
Last modified
2026-10-19 19:18:06.657000
View original CVE JSON
{
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-04-25T09:16:02.273",
"lastModified": "2026-10-19T19:18:06.657",
"vulnStatus": "Modified",
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ip6t_eui64: reject invalid MAC header for all packets\n\n`eui64_mt6()` derives a modified EUI-64 from the Ethernet source address\nand compares it with the low 64 bits of the IPv6 source address.\n\nThe existing guard only rejects an invalid MAC header when\n`par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()`\ncan still reach `eth_hdr(skb)` even when the MAC header is not valid.\n\nFix this by removing the `par->fragoff != 0` condition so that packets\nwith an invalid MAC header are rejected before accessing `eth_hdr(skb)`."
}
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