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 12ED4385D89 for ; Sat, 15 Aug 2026 06:37:39 +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=1786775860; cv=none; b=q2KHW0nf/36V/frjHYpup2hkBGle0uUtxZ8cD08GcVIMSCkMkS4ssrkjlBeqcnIlYfUaGIm49nz/xZvZeO+9dJKF9jonb7JG/YUF8g4x0ZmwdpFHcrtxyVuf8raE2JpcVotUjurKwVOSKhyQ42zzANsp6cOBK1Jq9co6p2nSqPY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775860; c=relaxed/simple; bh=zVknVrAP8x5en8LzZ+lfUBIRLZG3h2XxsjKZKcDVvFY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=eG+HNs3RGw+OCDrFdPz028SRt29XuIvAMiLXbWqMRjKRZ8jscO6pSi/hkhe8Udpy2EtVqWl4OkICaRDptxZY3W0bWlagGgaugyByocCy5ldkTLxgm3rlmAUKssY9zJAlPicAxoPG/calF0RAs+JokOcRAvodyn2kA/8AusWFBY4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hvCniaT+; 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="hvCniaT+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66ED11F000E9; Sat, 15 Aug 2026 06:37:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775859; bh=fRJ183RQOUnqFf4mQAS7K+GqoeS4aon2UfZWoXv24L0=; h=From:To:Cc:Subject:Date:Reply-To; b=hvCniaT+HbNkOYNVOVlAuQ8XFo5lhHYoeoKrWMeDoZWaHtFs0tIS+rHY18CwQ0O0Y 8v+0mSediHWSptqPyGL3yw03P0Z09VL2fHlEEoz0SHGEyHgp8jlspBAfopoTPGvyUF XXBUfgLDMHTdG9xxmREyWFMeACRAGTRx8ej1fMf4= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74339: ALSA: seq: Clear variable event pointer on read Date: Sat, 15 Aug 2026 15:11:06 +0900 Message-ID: <2026081557-CVE-2026-74339-9cd8@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=3639; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Y4oAICOZYfJ8ALMVdLlkTbezhxmjnKQUcfL4YEPrUHI=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNjIKfTzXt13wx575sr1JFQMH2C6z/fs11XSJdc1V66 fve5T+qO2JZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiStEMC6b5Hwvl+x4ax/S6 NKza1YFl0o9Cb4YFE7hnHUvgnjQzUTVmvdfaw6ut5vYyAQA= 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: ALSA: seq: Clear variable event pointer on read snd_seq_read() copies a queued variable-length event header to userspace before expanding the payload. Queued variable-length events use SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first extension cell. The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the copy, but it leaves data.ext.ptr untouched. A userspace sequencer client can therefore write a direct variable event to itself and read back the extension-cell kernel address from the returned header. Clear the temporary header pointer before copy_to_user(). The original queued event remains unchanged and is still passed to snd_seq_expand_var_event(), so payload expansion keeps using the internal chain. The Linux kernel CVE team has assigned CVE-2026-74339 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 5.15.212 with commit 14fe4f75fd5309d6b75f8e840ada88912b374207 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.1.178 with commit f29243c211928114f8b906e0a3fee77c236f14c8 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.6.145 with commit e0c3edd86414534cfd179fefe45b38c29c01ae7a Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.97 with commit 6b52211eba213c461f68922708a99d8190c1fcd5 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.18.40 with commit 74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.1.5 with commit c2ac9287e89916da684c2a548798351e63eb59ee Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.2-rc1 with commit 705dd6dcbc0ea87351c660c1a6443f85f1001c76 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-2026-74339 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/seq/seq_clientmgr.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/14fe4f75fd5309d6b75f8e840ada88912b374207 https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8 https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5 https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76