{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80976", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.810Z", "datePublished": "2026-09-11T19:42:38.215Z", "dateUpdated": "2026-10-19T08:46:00.756Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:46:00.756Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - End.DT6/End.DX6 run on the IPv6 receive path (ipv6_rthdr_rcv/lwtunnel_input/seg6_local_input_core) when a packet targets a configured local SID; a remote attacker who can route IPv6/SRv6 traffic to that SID on an SRv6 PE, VPN edge, or similar node triggers decap without local access.\nAC:L - The attacker fully controls the outer Hop-by-Hop and Destination Options chain that inflates IP6CB nhoff and the inner packet length, so one crafted packet deterministically makes ip6_protocol_deliver_rcu() index past the skb head with no race or uncontrolled layout.\nPR:N - SID processing runs in receive softirq with no authentication; a configured End.DT6/End.DX6 SID is an environmental precondition, not a credential the network attacker must hold (the same path is also reachable by an unprivileged userns user installing a SID).\nUI:N - Exploitation requires only sending crafted IPv6 packets to the SID; no victim user or administrator action is needed beyond the pre-existing SRv6 configuration.\nS:U - The stale-nhoff out-of-bounds access affects kernel memory on the receiving host only; it does not cross a VM, IOMMU, or sandbox security boundary.\nC:H - After decap, ip6_protocol_deliver_rcu() does skb_network_header(skb)[nhoff] using a stale outer nhoff the attacker can push thousands of bytes past the inner skb, which is an out-of-bounds kernel read; the leaked byte is then used as nexthdr, exposing further slab contents via dispatch side effects.\nI:H - Stale nhoff selects the inet6 protocol handler, type-confusing the inner packet into an attacker-influenced parser; IPv6 fragment reassembly also writes skb_network_header(skb)[nhoff], so the same attacker-controlled offset becomes an out-of-bounds write when the inner flow is fragmented.\nA:H - KASAN reports slab-out-of-bounds in ip6_protocol_deliver_rcu() on this path; in production a large nhoff lands on unmapped memory and oopses/panics the kernel, and the packet can be repeated at line rate." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/seg6_local.c" ], "versions": [ { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "d1f0d353358987ca87f21d8956e2d2854951130d", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "9ae92198c24d7dacd4070e2f34f6e1ed3a63061c", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "96c74420ac92930a7e0f21770818544eee4a93d7", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "2b154e96fcb3f01fd42765c64e0a56820fbc16eb", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "cfa186a0857a0f831dfca67b16bbc40ecfdf3280", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "c73fb911e02b9a766c950bc9707f3e3a96ffd702", "status": "affected", "versionType": "git" }, { "version": "d7a669dd2f8ba07a17423f4ad586dfc0379882f7", "lessThan": "f967455fb2a5a2079b9eb5823e9ccf359174bf9f", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/seg6_local.c" ], "versions": [ { "version": "4.14", "status": "affected" }, { "version": "0", "lessThan": "4.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d1f0d353358987ca87f21d8956e2d2854951130d" }, { "url": "https://git.kernel.org/stable/c/a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8" }, { "url": "https://git.kernel.org/stable/c/9ae92198c24d7dacd4070e2f34f6e1ed3a63061c" }, { "url": "https://git.kernel.org/stable/c/96c74420ac92930a7e0f21770818544eee4a93d7" }, { "url": "https://git.kernel.org/stable/c/2b154e96fcb3f01fd42765c64e0a56820fbc16eb" }, { "url": "https://git.kernel.org/stable/c/cfa186a0857a0f831dfca67b16bbc40ecfdf3280" }, { "url": "https://git.kernel.org/stable/c/c73fb911e02b9a766c950bc9707f3e3a96ffd702" }, { "url": "https://git.kernel.org/stable/c/f967455fb2a5a2079b9eb5823e9ccf359174bf9f" } ], "title": "seg6: reset IP6CB after IPv6 decapsulation", "x_generator": { "engine": "bippy-1.2.0" } } } }