CVE-2026-80976: linux
Vulnerability summary
CVE-2026-80976 is a critical (CVSS 9.8) vulnerability in linux. EPSS estimates a 0.71% chance of exploitation in the next 30 days, higher than 53% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 11 · Related 11Timeline
- 11-09-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: seg6: reset IP6CB after IPv6 decapsulation decap_and_validate() pulls the outer SRv6 headers and makes the inner packet the skb network header. The IPv6 control block still contains values collected while parsing the outer packet, including nhoff and extension-header flags. End.DX6 and End.DT6 route the inner IPv6 packet directly to the IPv6 input path. An unprivileged user can reach End.DT6 from a user and net namespace by installing a local SID and injecting an outer packet with Hop-by-Hop and Destination Options headers followed by an SRH and a minimal inner IPv6 packet. The outer extension headers leave a large nhoff in IP6CB. After decapsulation, ip6_protocol_deliver_rcu() uses that stale offset on the inner packet and reads beyond the skb head. KASAN reports: BUG: KASAN: slab-out-of-bounds in ip6_protocol_deliver_rcu ip6_protocol_deliver_rcu+0x1118/0x1450 ip6_input_finish+0x11b/0x240 seg6_local_input_core+0xed/0x2e0 lwtunnel_input+0x1e9/0x4e0 ipv6_rthdr_rcv+0x525f/0x6c50 ip6_protocol_deliver_rcu+0xcb7/0x1450 Before clearing IP6CB for an inner IPv6 packet, save its incoming interface index and L3 slave state. Restore both after the clear and set nhoff to the inner IPv6 base-header nexthdr field. Use IP6CB(skb)->iif rather than skb->skb_iif because VRF processing can replace skb_iif with the L3 master while IP6CB keeps the receiving interface. Preserve IP6SKB_L3SLAVE for the same reason.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.71%
Chance of exploitation in the next 30 days
Percentile
53%
Versus all other CVEs
30-day change
+0.01 pp
From 0.70% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu168 products
- linuxAll versions (No fix recorded)
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded)
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian2 products
- linuxAll versions (No fix recorded) | < 6.1.190-1 | < 6.12.111-1 | < 7.2.6-1
- linux-6.12< 6.12.111-1~deb12u1
Linux1 product
- linux≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < d1f0d353358987ca87f21d8956e2d2854951130d | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8 | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < 9ae92198c24d7dacd4070e2f34f6e1ed3a63061c | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < 96c74420ac92930a7e0f21770818544eee4a93d7 | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < 2b154e96fcb3f01fd42765c64e0a56820fbc16eb | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < cfa186a0857a0f831dfca67b16bbc40ecfdf3280 | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < c73fb911e02b9a766c950bc9707f3e3a96ffd702 | ≥ d7a669dd2f8ba07a17423f4ad586dfc0379882f7, < f967455fb2a5a2079b9eb5823e9ccf359174bf9f | 4.14
3 vendors · 171 products
