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 78144367F26 for ; Sun, 18 Oct 2026 15:17:11 +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=1792336632; cv=none; b=Yj7BRYsIrSRjFi/C75LXHMPQ3iaMhk/6zjYiFMJvcBiXnLOAQt5rY7abkuiqjHePBz/OKrfG8FBZfp03Njz3wWantVLGyx6Sgcz72flfrmm8u9joyxrVNe5ctcDOqKclCrom8aN5mXAyHF3WNtaBG7iGs1Va01wVZsu4jGni7kU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792336632; c=relaxed/simple; bh=TuH3AhFHkn4d/rCJ9WAKCdP8+bbzfvBie/b+hWaX0js=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jwobNglYp5OdA+7rj9f5vmHhSH8Xby+ARYiqkKWAVeCtwXmGCGvuOKYeU4SQQDuOePz/vBaNC0XPqrjvNXeeLZrEaAYzadc7M/FFuNirQr2G1x1mk1cEwwynvzfQdYnkkLc0h6mdwWTbdaQO/a+csInCgOm4ZRhtDe1h526Icoc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MsxTplWe; 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="MsxTplWe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C0C01F000C4; Sun, 18 Oct 2026 15:17:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792336631; bh=qEiB/r+aOh26n5zS1Fyf8BybR1hMnxXkUZdfrwFvgt8=; h=From:To:Cc:Subject:Date:Reply-To; b=MsxTplWeLSq1JGpyngpUJSxzFSq4rtMVC+NQdcCJ1HF+97hc5ZJHo3HIs3+nbC1Rq B1z8SE7beb92n9UfmY73tZFc3W1rvSNIHsjO8m4lmnwwGpfQTXL0cqQGkLn+GcOpj2 h2IkCZnoQP/Kq2XLde/s03wTVhkcJx0hN6XWcVTs= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-98441: net/sched: act_ct: avoid modifying shared unconfirmed ct entry Date: Sun, 18 Oct 2026 17:15:05 +0200 Message-ID: <2026101806-CVE-2026-98441-ae96@gregkh> X-Mailer: git-send-email 2.56.0 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=3725; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=qT7sd21DoHIFW3WOYE622sJQDFbGpsBqzH8nKFlNB2c=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlXHlWHaXnNSxY+yvxEVj/V+aKO38sjRn97bXf452Yfq Qp2XdfWEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABM5Mp9hwdzWc2s5P0u82M18 1vv+jcPvI2w8NjMs2GL929Ytb9Ob18HPDNJ9a5byrY9eAQA= 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: net/sched: act_ct: avoid modifying shared unconfirmed ct entry In a case where skb with an unconfirmed ct entry gets cloned, we may end up processing both again but with different sets of extensions. The series of events: 1. The first clone wants to commit and runs the helpers wiring up the extension pointer into the expectation list. 2. Then it looses the confirmation keeping the entry unconfirmed. 3. Second clone now wants to commit labels or run NAT and adds the new extension for that breaking the pointer in the expectation list causing UAF on the destruction path later. While this is possible to trigger, there should be no practical network pipeline where we need to process both clones without modifications in the same zone. So, let's just reset the entry in case for some reason we got an skb with a shared one. This doesn't affect any known use cases, but avoids any potential problems with sharing and modification of the unconfirmed ct entry. Unlike openvswitch module, act_ct allows for NAT without commit. Changing that would be a uAPI break. So, act_ct needs to reset on NAT regardless of the commit flag to avoid reallocation of the extension space. This, however, doesn't really change the picture for sensible networking cases as there should be no need to run the same packet twice (before and after the clone) through conntrack without packet header or zone changes and without commit. The fixes tag points to the introduction of helpers, since that's the main UAF trigger for the sharing. The Linux kernel CVE team has assigned CVE-2026-98441 to this issue. Affected and fixed versions =========================== Issue introduced in 6.2 with commit a21b06e7319129994f339ed47f512bbe57b77f5b and fixed in 6.12.112 with commit 2b783c562c3238ff50c34fd7a72a735c9cc73d9a Issue introduced in 6.2 with commit a21b06e7319129994f339ed47f512bbe57b77f5b and fixed in 6.18.55 with commit 4a04ed91575819fb1859311113e95700b709bec7 Issue introduced in 6.2 with commit a21b06e7319129994f339ed47f512bbe57b77f5b and fixed in 7.2.9 with commit b097d9d7a5b09c8ec5c4c1a08e35ac5a66b06b44 Issue introduced in 6.2 with commit a21b06e7319129994f339ed47f512bbe57b77f5b and fixed in 7.3-rc5 with commit f85009dfcd65e5969526b0db7a49b5413746e630 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-2026-98441 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/sched/act_ct.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/2b783c562c3238ff50c34fd7a72a735c9cc73d9a https://git.kernel.org/stable/c/4a04ed91575819fb1859311113e95700b709bec7 https://git.kernel.org/stable/c/b097d9d7a5b09c8ec5c4c1a08e35ac5a66b06b44 https://git.kernel.org/stable/c/f85009dfcd65e5969526b0db7a49b5413746e630