From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D66603F0757 for ; Fri, 8 May 2026 14:25:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250338; cv=none; b=aJIvX29DQEAsrC+lkfgwV4w/0kwQZ2HxVvysilefe4xHuDG1SZq/30Iu8+lMMV2dTJ+7oXO8YGgCRcFhhG08e6q9FASHLtTIb+tj3InzEmCAu39M2MdcphgIkUoSw+3rkWlVJeNDoNRNDu18xL5Iaqw0MvgCnIUxH90XTTGOnhA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250338; c=relaxed/simple; bh=SGmqUIBbQnOqYkpaHc1QWNzN6MuRYMYUz3kR7HqwmrY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=i4livP0qbDjp02Qhgt7s6Zby6t/Dkif2cWGGH3AXD3eXF5YQ0k2hG3njALzBUppSXZchzXU7H+UMkE7hWVKkY+mAhC/S0PZ1ImJqULXc8YVwu9mkCxMQowLK2RrncPEcYE7lQ7Dqd0WTtmaAeveIJ26gxhgF9970CavK6DYLgzY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GOsAstfE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GOsAstfE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6CD1DC2BCB0; Fri, 8 May 2026 14:25:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778250338; bh=SGmqUIBbQnOqYkpaHc1QWNzN6MuRYMYUz3kR7HqwmrY=; h=From:To:Cc:Subject:Date:Reply-To:From; b=GOsAstfEUS8OZeHMaJ3iRQkdBpAXoWwnB+oc3nkmM7B4Jl2dpF97GaxKSF4CyKqnd Zd9rBoy0Ad9D9Xe7T34bBfiHHc/VSuhJqIyJs4C7LmDZN4wopUIfg1DNSHPWYWuRK7 v4m2C9iWwtNo9MMtrt/JVkqtuKSz8qvLulWj4SMk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43437: ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain() Date: Fri, 8 May 2026 16:22:46 +0200 Message-ID: <2026050853-CVE-2026-43437-be27@gregkh> X-Mailer: git-send-email 2.54.0 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=3820; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=vBrc4GlgdWFask2FqTBPvXkKB2J8yBaWsuBeYrWQ4OU=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/PzbGS2Tut//08qzhqpeeu5kTZULd3As16vu0Yly3b ODcyvm2I5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACbCdZthvuNjea4cBd4vPuw3 X6yZ9P+9yQG1ywwLVnSskNG6k2p0OW9BkJpm6tEjVz/kAwA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain() In the drain loop, the local variable 'runtime' is reassigned to a linked stream's runtime (runtime = s->runtime at line 2157). After releasing the stream lock at line 2169, the code accesses runtime->no_period_wakeup, runtime->rate, and runtime->buffer_size (lines 2170-2178) — all referencing the linked stream's runtime without any lock or refcount protecting its lifetime. A concurrent close() on the linked stream's fd triggers snd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private() → snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime). No synchronization prevents kfree(runtime) from completing while the drain path dereferences the stale pointer. Fix by caching the needed runtime fields (no_period_wakeup, rate, buffer_size) into local variables while still holding the stream lock, and using the cached values after the lock is released. The Linux kernel CVE team has assigned CVE-2026-43437 to this issue. Affected and fixed versions =========================== Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 5.10.253 with commit 9baee36e8c5443411c4629afabafaff8a46a23fd Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 6.1.167 with commit fc71f888994569f87d5bee20b1ac6c9c1e3a7a79 Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 6.6.130 with commit 629cf09464cf98670996ea5c191dc9743e6f3f00 Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 6.12.78 with commit ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432 Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 6.18.19 with commit 4a758e9a1f5ed722f83c4dd35f867fe811553bcb Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 6.19.9 with commit c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694 Issue introduced in 3.0 with commit f2b3614cefb61ee6046a0aaee503ee37f227d310 and fixed in 7.0 with commit 9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6 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-2026-43437 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: sound/core/pcm_native.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/9baee36e8c5443411c4629afabafaff8a46a23fd https://git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79 https://git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00 https://git.kernel.org/stable/c/ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432 https://git.kernel.org/stable/c/4a758e9a1f5ed722f83c4dd35f867fe811553bcb https://git.kernel.org/stable/c/c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694 https://git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6