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CVE-2026-80976· NVD / CVE Program· CNA Linux

seg6: reset IP6CB after IPv6 decapsulation

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.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Sep 11, 2026
Updated
Sep 14, 2026
EPSS
0.8% · 53th percentile
CWE
—
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Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.14affected
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before d1f0d353358987ca87f21d8956e2d2854951130daffected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8affected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before 9ae92198c24d7dacd4070e2f34f6e1ed3a63061caffected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before 96c74420ac92930a7e0f21770818544eee4a93d7affected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before 2b154e96fcb3f01fd42765c64e0a56820fbc16ebaffected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before cfa186a0857a0f831dfca67b16bbc40ecfdf3280affected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before c73fb911e02b9a766c950bc9707f3e3a96ffd702affected · git
    • d7a669dd2f8ba07a17423f4ad586dfc0379882f7 and later · before f967455fb2a5a2079b9eb5823e9ccf359174bf9faffected · git
    • before 4.14not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxall versions—
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan
  • CVE-2026-74309vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
    40Plan
  • CVE-2026-74280crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
    40Plan
  • CVE-2026-74279crypto: cavium/cpt - fix DMA cleanup using wrong loop index
    40Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux2b154e96fcb3f01fd42765c64e0a56820fbc16ebVendor (CNA)
Linux Linux96c74420ac92930a7e0f21770818544eee4a93d7Vendor (CNA)
Linux Linux9ae92198c24d7dacd4070e2f34f6e1ed3a63061cVendor (CNA)
Linux Linuxa0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8Vendor (CNA)
Linux Linuxc73fb911e02b9a766c950bc9707f3e3a96ffd702Vendor (CNA)
Linux Linuxcfa186a0857a0f831dfca67b16bbc40ecfdf3280Vendor (CNA)
Linux Linuxd1f0d353358987ca87f21d8956e2d2854951130dVendor (CNA)
Linux Linuxf967455fb2a5a2079b9eb5823e9ccf359174bf9fVendor (CNA)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records