Use-after-free in Linux kernel xfrm compat ALLOCSPI requests
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
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- 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 xfrm ALLOCSPI handling translates the response for compat requests twice, so a compat request is read four bytes past its declared payload and the translated child is attached to the request. A multicast clone of the request can observe that child, which is freed after the handler returns while a compat receiver may still read it, causing a use-after-free.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: xfrm: fix compat ALLOCSPI request use-after-free xfrm_state_netlink() builds the ALLOCSPI response with dump_one_state(), which already calls alloc_compat() with the response skb and header. xfrm_alloc_userspi() then calls alloc_compat() again, but passes the original request skb and its header. For a compat request, the translator therefore interprets the 228-byte compat xfrm_userspi_info as the 232-byte native layout and reads four bytes past the declared payload. It also publishes the translated child through the request's frag_list. A multicast clone of the request shares skb_shared_info and can observe that child. xfrm_user_rcv_msg() frees it after the request handler returns, racing a compat receiver which may still be copying from it and resulting in a use-after-free. Remove the redundant conversion. The response keeps its correct compat translation from dump_one_state(), and no child is attached to the inbound request.
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, 6.18.54, 7.2.8 or 7.3, depending on the branch in use. Red Hat Enterprise Linux 6 has no fix planned, and Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 and Red Hat OpenShift Container Platform 5 have no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 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 |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Not affected: 3 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-06 Threatist record created from CVE-2026-98370
- 2026-10-06 Alias added: GHSA-xf8r-gcp9-vg22
- 2026-10-09 Affected versions changed · Red Hat
- 2026-10-09 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/494f2bee9d8d0ebcfa249ac41bed7fed26d119b4
- https://git.kernel.org/stable/c/17893987e52918c23945c42e47e894a936305a25
- https://git.kernel.org/stable/c/42971ea17c7a8afc0bdd5ca40648bf4e5bb7b810
- https://git.kernel.org/stable/c/2b63341e2ebc9b6f73cbd9214dbe7d46dd98c718
- https://git.kernel.org/stable/c/bb63ab52a18273ec68340ac49aebbaa7b514ccd5
- https://git.kernel.org/stable/c/248433942155b42a0ef04a5806c8aca024ea7c33
- https://git.kernel.org/stable/c/e70f639aee2ff0def155c256cace9e0f81d998e2
- https://git.kernel.org/stable/c/d1ebd9081879fd9ae9c8fb7e8928f19cc88ae320
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Sources
- CVE-2026-98370 · CVE Program
- CVE-2026-98370 · NVD
- FIRST EPSS
- GHSA-xf8r-gcp9-vg22 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98370 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences