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 D467657F732 for ; Fri, 11 Sep 2026 19:52:31 +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=1789156362; cv=none; b=MmkGCFG9QK3t3HbsFo5zH5cjV7hFnYjojnGxQtbPIV5d8CpNCqMq5K3Sh5N+JKmixM6rOG5YnbERKOfwD1DFf1jvoBQ/6Kjb7UMomPK6Da3/ha0RPcybxsWqI0Uwxizxe7miFBfYSSA4FNRQd6ZtHqJp2ZDNjhaixTx+9GH/Jzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156362; c=relaxed/simple; bh=Ix/fq4Od0geshC9FtIsc9a6Mn4K9u6OPSZ1nb/CR6cw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=F8wq4gHoTd7yEw1Q95+sFvD3uyKIszEnf+74ZKW2iajS09MX/Eu+M/H5bO6zok22eB5Rs8kNEqGkJtF/XVkpvTjmv1zTtASWQCdXPm2XvQAa5ofyY+u4tyK6TP8yrkmeSqf6zprF4bmejXNgVAiSXboGttK+jR9KBeasYWKOOjU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=a8ONcm3I; 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="a8ONcm3I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B9E81F00899; Fri, 11 Sep 2026 19:52:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156348; bh=h/mR7x0re3nLU6QxW/jVVBhaY+7j76lBZVXu57DFL24=; h=From:To:Cc:Subject:Date:Reply-To; b=a8ONcm3InvpiBddHRQ+WpRRxr+6SCfccqMun/mEwqSK172F+TVwhPJQmyxXyIQ1aU HAUiMfZGbilAI87hmyAfrpdN+jzN/va0Ax7jMpv3XbMcp7i43aWlbdn/F2m2MKrtU3 CwifLjaecYxEfVdI0x/y0EWOFcj/gVlfzLeqLEPI= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89488: openvswitch: Fix CT limit teardown use-after-free Date: Fri, 11 Sep 2026 21:42:57 +0200 Message-ID: <2026091107-CVE-2026-89488-120f@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=3335; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=btmsNARmsJGQAkt9Bb7A02IikA2cPRswklZiM+aPdq4=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIoPTtOdYxevt91kl4jCVff2hi6eKzpWd9LDSOjF5j kBQsePEjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZiIlwrDXNlbvHoRGs9m/TOY 3PLm8iptwTC5EoYFM989WHk/h61q9UQ9ybQD/fmx2q8rAA== 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: openvswitch: Fix CT limit teardown use-after-free Packet processing uses CT limit state under RCU, while netns teardown frees that state under ovs_mutex. The CT limit pointer was neither removed from readers nor protected by a grace period, allowing packet processing to dereference the freed state. An unprivileged user can trigger this bug from a user and network namespace, causing a slab-use-after-free in ovs_ct_execute() when the netns is torn down. Publish the CT limit pointer through RCU, remove it before teardown, and wait for readers before freeing its contents. Keep ovs_mutex around individual CT limit updates, and use the RCU read-side lock while GET traverses the RCU-protected limit lists. Netns teardown detaches the RCU-protected CT limit state in the pernet .pre_exit callback while holding ovs_mutex. The pernet core guarantees an RCU grace period between the .pre_exit and .exit callbacks, so the .exit callback completes the teardown without adding any extra synchronization. The netlink command handlers do not need NULL checks because the userspace netlink socket holds an active reference to its network namespace while a request is processed. The per-netns exit path therefore cannot run concurrently with SET, DEL, or GET for that socket's namespace. The Linux kernel CVE team has assigned CVE-2026-89488 to this issue. Affected and fixed versions =========================== Issue introduced in 4.18 with commit 11efd5cb04a184eea4f57b68ea63dddd463158d1 and fixed in 6.18.51 with commit e15407c3a8a005324f633cd46cd8fb58042c1157 Issue introduced in 4.18 with commit 11efd5cb04a184eea4f57b68ea63dddd463158d1 and fixed in 7.2.4 with commit 6a6d36fadb8537d9b79e72c9fa51885ec0c33e10 Issue introduced in 4.18 with commit 11efd5cb04a184eea4f57b68ea63dddd463158d1 and fixed in 7.3-rc1 with commit 403f96c32c9e24600093d7d0c61c17daeedca957 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-2026-89488 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/openvswitch/conntrack.c net/openvswitch/conntrack.h net/openvswitch/datapath.c net/openvswitch/datapath.h 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/e15407c3a8a005324f633cd46cd8fb58042c1157 https://git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10 https://git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957