Out-of-bounds read in Linux kernel XSK map lookup
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel from 5.5 is affected by an out-of-bounds read in the XSK map lookup code. The generated lookup compares a 32-bit key against max_entries using a sign-extended 64-bit immediate, so a max_entries value of 0x80000000 or higher skips the bounds check and an out-of-range index reads past xsk_map[].
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: xsk: Use a 32-bit compare in xsk_map_gen_lookup xsk_map_gen_lookup() loads a u32 key and compares it with max_entries using BPF_JMP_IMM. BPF immediates are sign-extended to 64 bits, so a max_entries value of 0x80000000 or higher becomes a threshold larger than every zero-extended 32-bit key. An out-of-range index then skips the bounds check and the generated lookup reads past xsk_map[]. Compare with BPF_JMP32_IMM so the check stays in 32-bit unsigned range.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9 or 7.3. Red Hat rates it Moderate and lists Red Hat Enterprise Linux 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98631
- 2026-10-18 Alias added: GHSA-r8m8-f9qq-5h53
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score added · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/c6d5c582d55a8f229d75e98d62eaa065b0deb18d
- https://git.kernel.org/stable/c/227ec890559e922e235eb543646e3bf0bd8269b0
- https://git.kernel.org/stable/c/11d9be35c1f4233798e99be98bc474f83a254c6c
- https://git.kernel.org/stable/c/123f90f394ca404ab8796a7c8072ff7fa5b65a9c
- https://git.kernel.org/stable/c/36461e58f88a1b723f86693f437ac12e60ff4363
- https://git.kernel.org/stable/c/b5c0cff0c5331582ab01c4c423731453a8381acc
- https://git.kernel.org/stable/c/3c1e0a4bc156b8d5c5772dbc76b9ea74dce5ca24
- https://git.kernel.org/stable/c/70504de0bb627848667207bec7ccfd647deb8814
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Sources
- CVE-2026-98631 · CVE Program
- CVE-2026-98631 · NVD
- FIRST EPSS
- GHSA-r8m8-f9qq-5h53 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98631 · Red Hat security data · CC BY 4.0
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