{"cve":"CVE-2026-80976","nvd":{"published":"2026-09-11T20:19:03.887","modified":"2026-10-19T09:17:29.663","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nseg6: reset IP6CB after IPv6 decapsulation\n\ndecap_and_validate() pulls the outer SRv6 headers and makes the inner\npacket the skb network header. The IPv6 control block still contains\nvalues collected while parsing the outer packet, including nhoff and\nextension-header flags.\n\nEnd.DX6 and End.DT6 route the inner IPv6 packet directly to the IPv6\ninput path. An unprivileged user can reach End.DT6 from a user and net\nnamespace by installing a local SID and injecting an outer packet with\nHop-by-Hop and Destination Options headers followed by an SRH and a\nminimal inner IPv6 packet.\n\nThe outer extension headers leave a large nhoff in IP6CB. After\ndecapsulation, ip6_protocol_deliver_rcu() uses that stale offset on the\ninner packet and reads beyond the skb head. KASAN reports:\n\n  BUG: KASAN: slab-out-of-bounds in ip6_protocol_deliver_rcu\n  ip6_protocol_deliver_rcu+0x1118/0x1450\n  ip6_input_finish+0x11b/0x240\n  seg6_local_input_core+0xed/0x2e0\n  lwtunnel_input+0x1e9/0x4e0\n  ipv6_rthdr_rcv+0x525f/0x6c50\n  ip6_protocol_deliver_rcu+0xcb7/0x1450\n\nBefore clearing IP6CB for an inner IPv6 packet, save its incoming\ninterface index and L3 slave state. Restore both after the clear and set\nnhoff to the inner IPv6 base-header nexthdr field.\n\nUse IP6CB(skb)->iif rather than skb->skb_iif because VRF processing can\nreplace skb_iif with the L3 master while IP6CB keeps the receiving\ninterface. Preserve IP6SKB_L3SLAVE for the same reason.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":[],"references":["https://git.kernel.org/stable/c/2b154e96fcb3f01fd42765c64e0a56820fbc16eb","https://git.kernel.org/stable/c/96c74420ac92930a7e0f21770818544eee4a93d7","https://git.kernel.org/stable/c/9ae92198c24d7dacd4070e2f34f6e1ed3a63061c","https://git.kernel.org/stable/c/a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8","https://git.kernel.org/stable/c/c73fb911e02b9a766c950bc9707f3e3a96ffd702"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-80976","score":0.00714,"percentile":0.53394,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}