From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1C34F518143 for ; Thu, 17 Sep 2026 16:38:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663132; cv=none; b=cP2fdsBgJuyw7txpKZ4IWZfszFLgaxIie/vJIzxyqkxA5/GUx3vNYv2xn9H5W2WLfK05fgi2ZQgq27taux9X6D+HzzA4wy1CkKU04iqEHUmlI1Xd52R2PhF6PUCsH+tYA8UReHCSYWPOiPh33DWeV9s9k/5rCrPuTDIY8Kxxz1I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663132; c=relaxed/simple; bh=sAxpJNKzxoP+oTKmE79eppTzRq8aWCvM68hXywAW4Wk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IJJvjSFSSDdNChdZTYWlICpyL3eKm4MrJoa48CdgROXSfWaViV5RRgCj1UtB38hkDvhah0dOwFS9Nj1H5bq73SHd4ALGX4AFnYN9f/ASYERYMpxWTIc+XWWJJ33bNAFxEf8cx1AxRCqu99MqbsEhq6ZAwhfHMsDwA0o2+k1v90M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oQBx8894; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="oQBx8894" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 477801F000FF; Thu, 17 Sep 2026 16:38:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789663129; bh=+b1B+i2itwKLH0PHPc+otC44E9RnFtSnZ46LgRgKxTg=; h=From:To:Cc:Subject:Date:Reply-To; b=oQBx8894wvcAZOskL5CyT6vl8lIBza2vuPKFZR9M1h/W5jfC4A0m7eAgNW2Wge7Yu jvuFko1cvmBfQwiikGGPDDgt/U6weVWtyANUxqoTDXCufAlToxj2DFNTctp+6FrCwy Pu2Kz3kirPv6Koh4MjCHUDkvaIVivOQcTd7t658U= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-93138: bpf: Fix vmlinux BTF prep race in bpf_get_btf_vmlinux Date: Thu, 17 Sep 2026 17:16:55 +0100 Message-ID: <2026091753-CVE-2026-93138-0f4e@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4111; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=azDqwzPLHbfEqPbusuz4hCDeSAsHqZPlS2NPtczYmBk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBC6KKspmrEucccJH9vWn1wFh+r+2cB8V0mmT7NIUd Z3cGn++I5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACbSk86wYHl88/JMYbc5RSwd T44fWv707XLFDoZ5OvazCvWZX6fvW2sxoZptosCluJ/lAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman 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. The Linux kernel CVE team has assigned CVE-2026-93138 to this issue. Affected and fixed versions =========================== Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 5.10.270 with commit f32a4a40bc635be25d6816da4bd91e9e58c31bf3 Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 5.15.221 with commit a7fe72d780122eb934536f1719abad445f6afdf7 Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 6.1.188 with commit e18a10b39c994f04e1ebd7f8fc042bb1ca8ad053 Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 6.6.157 with commit 978524ecfc1c539282df5858de1eec20748c6f74 Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 6.12.110 with commit eaf302628a78806f66d8224d6ba03fb4d5025de4 Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 6.18.52 with commit 2892f3f44bf865c8fb6b6c0960edec4cc91806ee Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 7.2.6 with commit 86d11c594d60b255b526fa5260f669463fb1a063 Issue introduced in 5.5 with commit 8580ac9404f6240668a026785d7d8856f0530409 and fixed in 7.3-rc1 with commit 92863e678070f57c17c868e4bfa2441a5c61ad2b Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-93138 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: kernel/bpf/verifier.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: 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