{"id":"CVE-2026-80976","revision":"c641325c3d55450f802d612418ebd628","records":[{"revision":"c641325c3d55450f802d612418ebd628","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-80976","aliases":[],"title":"seg6: reset IP6CB after IPv6 decapsulation","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.","state":0,"publishedAt":"2026-09-11T19:42:38.215+00:00","modifiedAt":"2026-10-19T08:46:00.756+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv6/seg6_local.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"d1f0d353358987ca87f21d8956e2d2854951130d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"9ae92198c24d7dacd4070e2f34f6e1ed3a63061c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"96c74420ac92930a7e0f21770818544eee4a93d7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"2b154e96fcb3f01fd42765c64e0a56820fbc16eb\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"cfa186a0857a0f831dfca67b16bbc40ecfdf3280\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"c73fb911e02b9a766c950bc9707f3e3a96ffd702\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d7a669dd2f8ba07a17423f4ad586dfc0379882f7\",\n                            \"lessThan\": \"f967455fb2a5a2079b9eb5823e9ccf359174bf9f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv6/seg6_local.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 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,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/d1f0d353358987ca87f21d8956e2d2854951130d","https://git.kernel.org/stable/c/a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8","https://git.kernel.org/stable/c/9ae92198c24d7dacd4070e2f34f6e1ed3a63061c","https://git.kernel.org/stable/c/96c74420ac92930a7e0f21770818544eee4a93d7","https://git.kernel.org/stable/c/2b154e96fcb3f01fd42765c64e0a56820fbc16eb","https://git.kernel.org/stable/c/cfa186a0857a0f831dfca67b16bbc40ecfdf3280","https://git.kernel.org/stable/c/c73fb911e02b9a766c950bc9707f3e3a96ffd702","https://git.kernel.org/stable/c/f967455fb2a5a2079b9eb5823e9ccf359174bf9f"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80976","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-80976","identifiers":["CVE-2026-80976"]},"retained":false,"historicalAffected":[]}],"coverage":[]}