{"api_version":"1","generated_at":"2026-09-20T14:40:21+00:00","cve":"CVE-2026-80976","urls":{"html":"https://cve.report/CVE-2026-80976","api":"https://cve.report/api/cve/CVE-2026-80976.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80976","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80976"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:03","updated_at":"2026-09-14 13:18:52"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/2b154e96fcb3f01fd42765c64e0a56820fbc16eb","name":"https://git.kernel.org/stable/c/2b154e96fcb3f01fd42765c64e0a56820fbc16eb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9ae92198c24d7dacd4070e2f34f6e1ed3a63061c","name":"https://git.kernel.org/stable/c/9ae92198c24d7dacd4070e2f34f6e1ed3a63061c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c73fb911e02b9a766c950bc9707f3e3a96ffd702","name":"https://git.kernel.org/stable/c/c73fb911e02b9a766c950bc9707f3e3a96ffd702","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/96c74420ac92930a7e0f21770818544eee4a93d7","name":"https://git.kernel.org/stable/c/96c74420ac92930a7e0f21770818544eee4a93d7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f967455fb2a5a2079b9eb5823e9ccf359174bf9f","name":"https://git.kernel.org/stable/c/f967455fb2a5a2079b9eb5823e9ccf359174bf9f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8","name":"https://git.kernel.org/stable/c/a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cfa186a0857a0f831dfca67b16bbc40ecfdf3280","name":"https://git.kernel.org/stable/c/cfa186a0857a0f831dfca67b16bbc40ecfdf3280","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d1f0d353358987ca87f21d8956e2d2854951130d","name":"https://git.kernel.org/stable/c/d1f0d353358987ca87f21d8956e2d2854951130d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80976","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80976","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 d1f0d353358987ca87f21d8956e2d2854951130d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 9ae92198c24d7dacd4070e2f34f6e1ed3a63061c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 96c74420ac92930a7e0f21770818544eee4a93d7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 2b154e96fcb3f01fd42765c64e0a56820fbc16eb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 cfa186a0857a0f831dfca67b16bbc40ecfdf3280 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 c73fb911e02b9a766c950bc9707f3e3a96ffd702 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7a669dd2f8ba07a17423f4ad586dfc0379882f7 f967455fb2a5a2079b9eb5823e9ccf359174bf9f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.270 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.221 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.188 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.157 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80976","cve":"CVE-2026-80976","epss":"0.006260000","percentile":"0.481060000","score_date":"2026-09-14","updated_at":"2026-09-15 00:00:42"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv6/seg6_local.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"d1f0d353358987ca87f21d8956e2d2854951130d","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"9ae92198c24d7dacd4070e2f34f6e1ed3a63061c","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"96c74420ac92930a7e0f21770818544eee4a93d7","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"2b154e96fcb3f01fd42765c64e0a56820fbc16eb","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"cfa186a0857a0f831dfca67b16bbc40ecfdf3280","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"c73fb911e02b9a766c950bc9707f3e3a96ffd702","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"},{"lessThan":"f967455fb2a5a2079b9eb5823e9ccf359174bf9f","status":"affected","version":"d7a669dd2f8ba07a17423f4ad586dfc0379882f7","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv6/seg6_local.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.14"},{"lessThan":"4.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.270","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.221","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.188","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.157","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.109","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.270","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.221","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.188","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"4.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"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."}]}],"providerMetadata":{"dateUpdated":"2026-09-14T11:59:21.393Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80976","datePublished":"2026-09-11T19:42:38.215Z","dateReserved":"2026-08-26T14:34:25.810Z","dateUpdated":"2026-09-14T11:59:21.393Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:03","lastModifiedDate":"2026-09-14 13:18:52","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80976","Ordinal":"1","Title":"seg6: reset IP6CB after IPv6 decapsulation","CVE":"CVE-2026-80976","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80976","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"seg6: reset IP6CB after IPv6 decapsulation"}]}}}