CVE-2026-93138: Linux Vulnerability (CVSS 7.8)

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.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 8580ac9404f6240668a026785d7d8856f0530409, < f32a4a40bc635be25d6816da4bd91e9e58c31bf3; >= 8580ac9404f6240668a026785d7d8856f0530409, < a7fe72d780122eb934536f1719abad445f6afdf7; >= 8580ac9404f6240668a026785d7d8856f0530409, < e18a10b39c994f04e1ebd7f8fc042bb1ca8ad053; >= 8580ac9404f6240668a026785d7d8856f0530409, < 978524ecfc1c539282df5858de1eec20748c6f74; >= 8580ac9404f6240668a026785d7d8856f0530409, < eaf302628a78806f66d8224d6ba03fb4d5025de4; >= 8580ac9404f6240668a026785d7d8856f0530409, < 2892f3f44bf865c8fb6b6c0960edec4cc91806ee; >= 8580ac9404f6240668a026785d7d8856f0530409, < 86d11c594d60b255b526fa5260f669463fb1a063; >= 8580ac9404f6240668a026785d7d8856f0530409, < 92863e678070f57c17c868e4bfa2441a5c61ad2b
Linux	Linux	5.5

References

Timeline

Published: Sep 17, 2026
Last Modified: Sep 18, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-93138?

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.

How severe is CVE-2026-93138?

CVE-2026-93138 has a CVSS score of 7.8/10 (HIGH severity).

How do I fix CVE-2026-93138?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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