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CVE-2026-93138

Published: September 19, 2026Last modified: October 6, 2026

Description

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.

Severity score breakdown

ParameterValue
Base score7.8
Attack VectorLOCAL
Attack complexityLOW
Privileges requiredLOW
User interactionNONE
ScopeUNCHANGED
ConfidentialityHIGH
Integrity impactHIGH
Availability impactHIGH
VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Status

ProductReleasePackageStatus
Alpaquita Linux23 LTSlinux-ltsFixed (6.1.189-r0)
25 LTSlinux-ltsFixed (6.12.111-r0)
Streamlinux-ltsFixed (6.18.53-r0)

References

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