bpf: Fix vmlinux BTF prep race in bpf_get_btf_vmlinux
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix vmlinux BTF prep race in bpf_get_btf_vmlinux bpf_get_btf_vmlinux() lazily parses the vmlinux BTF under the bpf_verifier_lock, but publishes the result through a plain store and re-checks it through a plain lockless load. Nothing orders the stores initializing the struct btf inside btf_parse_vmlinux() against the store publishing the pointer: On a weakly ordered arch, a concurrent first-time caller taking the lockless fast path could in principle observe the pointer before the parsed contents are visible. The mutex_unlock() does not help such a reader given it only synchronizes with a later acquisition of the same lock. Thus, publish the pointer with smp_store_release() and read it on the fast path with smp_load_acquire(). Acquire semantics are needed rather than a dependency-ordered READ_ONCE(): btf_parse_vmlinux() also populates globals outside the returned object (e.g. bpf_ctx_convert.t). An address dependency would only order accesses performed through the pointer and not cover other globals.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 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
- 2026-10-02 Threatist record created from CVE-2026-93138
- 2026-10-03 Alias added: GHSA-j9m2-mp7m-3w46
- 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
- 2026-11-01 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/f32a4a40bc635be25d6816da4bd91e9e58c31bf3
- https://git.kernel.org/stable/c/a7fe72d780122eb934536f1719abad445f6afdf7
- https://git.kernel.org/stable/c/e18a10b39c994f04e1ebd7f8fc042bb1ca8ad053
- https://git.kernel.org/stable/c/978524ecfc1c539282df5858de1eec20748c6f74
- https://git.kernel.org/stable/c/eaf302628a78806f66d8224d6ba03fb4d5025de4
- https://git.kernel.org/stable/c/2892f3f44bf865c8fb6b6c0960edec4cc91806ee
- https://git.kernel.org/stable/c/86d11c594d60b255b526fa5260f669463fb1a063
- https://git.kernel.org/stable/c/92863e678070f57c17c868e4bfa2441a5c61ad2b
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Sources
- CVE-2026-93138 · CVE Program
- CVE-2026-93138 · NVD
- FIRST EPSS
- GHSA-j9m2-mp7m-3w46 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-93138 · Red Hat security data · CC BY 4.0
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