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 102C3381EA7 for ; Sat, 15 Aug 2026 06:33:29 +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=1786775610; cv=none; b=KzAlYZWA+CqN+gHHbrygwOaNLpMe/AqIqfuTmcKnqIE6zU9XTjnLal/mGHJ8GISq5K0RxFh1Qs5N4qtAaB3Yq+2SiZL53MnHzV8CKpMYafswDswe9T8ezeDHJ3NCF9Tch3QttObr+hxB0iMZYT4jm863uCxprYr/2JMXxghSGAQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775610; c=relaxed/simple; bh=l5j0YwKmHuwNGinrIj2alYhI1dSGIMXalqJRlDb0Elg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=NuTPIBLnGIP1Rv3tM1EXIysKTJZeCyzEKJ/oVIF+VpNF5iND27YZZKMKdk2mhQLZ+zXfuTyAfAGP6bA5nprv85Ar05Bdmqiosm9ZjvHSOUYgEcaHsljHFFKt9PtoPGjOjobIcRLYyzFDDSRZDDWPtAya4+5QL0YvH8Y4IUb2TwM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EuM7cvw4; 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="EuM7cvw4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 653211F000E9; Sat, 15 Aug 2026 06:33:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775609; bh=5rxC/P3MueIC6WhbSEwMKkTTQ6MrxT5RVpaeK5zAsls=; h=From:To:Cc:Subject:Date:Reply-To; b=EuM7cvw41TqjCXZaKRwRTA1f22ofBam7vx0jx8iWcFKBGIxW6bkaZwCtk+QiSqaV6 zkLIqcB7fQ7AN9tFdrDBAemXNwqE9UJ9embeOtub+xz2ttbW1nakITDbBMf3HFrvUk fQCv2MG+cbWUHD4UH7bfYmI8GO49vj7QWYGJW8+M= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74255: tipc: fix UAF in tipc_l2_send_msg() Date: Sat, 15 Aug 2026 15:09:42 +0900 Message-ID: <2026081541-CVE-2026-74255-caef@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=3993; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=KXfXDw0djwLVoLruf1DJa+p96Y5ISxMeOZCl4mOmGqg=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNjIy/Tvd9eb+4lXMq38z3lattfTozP7hrBB5UvyiTJ RoSek2vI5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACZySIthnlLYYbf5xp9OXZj6 43Ha+rtHXxVsrmCYKxDO9b2PYVPtguMaf2N0T8+sfrjXEAA= 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: tipc: fix UAF in tipc_l2_send_msg() Syzbot reported a slab-use-after-free in ipvlan_hard_header() when called from tipc_l2_send_msg(). The root cause is that tipc_disable_l2_media() calls synchronize_net() while b->media_ptr is still valid. This allows concurrent RCU readers to obtain the device pointer after synchronize_net() has finished. The pointer is cleared later in bearer_disable(), but without any subsequent synchronization, allowing the device to be freed while still in use by readers. Fix this by clearing b->media_ptr in tipc_disable_l2_media() before calling synchronize_net(). This is safe to do now because the call order in bearer_disable() was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic") to call tipc_node_delete_links() (which needs the pointer) before disable_media(). https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u The Linux kernel CVE team has assigned CVE-2026-74255 to this issue. Affected and fixed versions =========================== Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 5.10.261 with commit 609ced2301be1df7e7ed2ef47d1d916674e6ba3b Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 5.15.212 with commit 71aafa16d79b107b33837f60b6cbc7d0cb8c5708 Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 6.1.178 with commit f4002f1c669cc02e3763f479fc25ff1dfa9e2420 Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 6.6.145 with commit 50ff092633b06382e5091dd5b093ce943d4ac2f9 Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 6.12.97 with commit aef12b5ce793dea6b3a97a58fd0f946000ae8945 Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 6.18.40 with commit 0d8a12d7143126afdf9fbe2e3d438650dd6603ed Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 7.1.5 with commit 35e0297a93c3c34a3924eeef816c03504e3ab5c5 Issue introduced in 4.4 with commit 282b3a056225b35024246f63feb91d769d714dad and fixed in 7.2-rc1 with commit f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6 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-2026-74255 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: net/tipc/bearer.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/609ced2301be1df7e7ed2ef47d1d916674e6ba3b https://git.kernel.org/stable/c/71aafa16d79b107b33837f60b6cbc7d0cb8c5708 https://git.kernel.org/stable/c/f4002f1c669cc02e3763f479fc25ff1dfa9e2420 https://git.kernel.org/stable/c/50ff092633b06382e5091dd5b093ce943d4ac2f9 https://git.kernel.org/stable/c/aef12b5ce793dea6b3a97a58fd0f946000ae8945 https://git.kernel.org/stable/c/0d8a12d7143126afdf9fbe2e3d438650dd6603ed https://git.kernel.org/stable/c/35e0297a93c3c34a3924eeef816c03504e3ab5c5 https://git.kernel.org/stable/c/f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6