Local out-of-bounds read via stale IP6CB offset
Published Sep 11, 2026 · Updated Sep 11, 2026
Out-of-bounds read in Linux seg6 IPv6 decapsulation allows local users to read beyond an inner packet buffer in 4.14 and affected Git revisions. decap_and_validate() replaces the network header with the inner IPv6 packet but leaves the outer packet's nhoff in IP6CB, so ip6_protocol_deliver_rcu() applies a stale offset beyond the skb head. Exploitation requires an unprivileged user and network namespace, a local End.DT6 SID, and a crafted outer packet with extension headers and an SRH; the demonstrated consequence is a KASAN-detected slab out-of-bounds read.
Summary
What happened
Out-of-bounds read in Linux seg6 IPv6 decapsulation allows local users to read beyond an inner packet buffer in 4.14 and affected Git revisions. decap_and_validate() replaces the network header with the inner IPv6 packet but leaves the outer packet's nhoff in IP6CB, so ip6_protocol_deliver_rcu() applies a stale offset beyond the skb head. Exploitation requires an unprivileged user and network namespace, a local End.DT6 SID, and a crafted outer packet with extension headers and an SRH; the demonstrated consequence is a KASAN-detected slab out-of-bounds read.
The record
- CVE
- CVE-2026-80976
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.14
- Affected versionversion=d7a669dd2f8ba07a17423f4ad586dfc0379882f7 <2b154e96fcb3f01fd42765c64e0a56820fbc16eb
- Affected versionversion=d7a669dd2f8ba07a17423f4ad586dfc0379882f7 <c73fb911e02b9a766c950bc9707f3e3a96ffd702
- Affected versionversion=d7a669dd2f8ba07a17423f4ad586dfc0379882f7 <cfa186a0857a0f831dfca67b16bbc40ecfdf3280
- Affected versionversion=d7a669dd2f8ba07a17423f4ad586dfc0379882f7 <f967455fb2a5a2079b9eb5823e9ccf359174bf9f
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
- Upstream End.DT6 reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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