From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792759393; b=wHdzGT5F8Cipvjh05mJqTW8bWuDnI5CEpBZDvBOZlAAIGab/j2dV0c/9RlxrFtcPzSHv iqirZjbdvDCH+SwNdwBe6anTa70wdNpqlX8G9b2bDM+sjpigEIBy3MRKtz8t7xhMHpe+Q 4GrDOW8BTVH6yylhE/hMFBsQX11P9S1TcYTmzrpZI7gUxj9QQV3xoOgDshMgC4RdFEOFp 0ahmeWGB6nr0b0OUjQ08s0mDlnXoxrgLbhTvGJAVvzvP+8L8sUMz9clvYlhV688gsdNLT ljvWFxTtjkt+Vji4wxAVTgxZPdvJjgC2FtOB07ghHB2/3na/WMRciNwfst6ylZLHvZQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792759393; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: Reply-To:MIME-Version:Lines:X-Developer-Signature:X-Developer-Key: Content-Transfer-Encoding; bh=GjRSINja69xrZxI1wZtPSi8IA0kkaNamIyf0LQpgV+k=; b=GhqjcIM4hNgoX5dehSUM3k1sF4kcyRhdG0hpHXHx5ejUPJFgTJ0nUy4ht4beYAeUWbx8 v+oTpLRdCsxogpnLARax7qWjANQJuqRxrjyqDGlc48/6BjlzQ76oRqbU/0R7L+4GEqqMq b0nF83QFcxISzlEcnhj1LTcIJ3hY6bo5HxaBKRIRNatQz5qiSx4O0AzT5lJHuZoQ1Y+1j Hcf1a3ejRhepRQ2Ms2xqohDhDUd9fVd9HJeNxx9Lc/qgvYBPfO5ihNFqkQj7LGg0p6qrW i02hF38jzq86ogZX8Z7NH3KieFv/woG4SCOpUIKL1qZfpin355K9/fIj8zXuwQeAxyw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=P94d+vLI; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EBF31606A31B for ; Fri, 23 Oct 2026 12:43:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=P94d+vLI Received: by smtp.kernel.org (Postfix) with ESMTPSA id 200091F01825; Fri, 23 Oct 2026 12:43:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792759392; bh=GjRSINja69xrZxI1wZtPSi8IA0kkaNamIyf0LQpgV+k=; h=From:To:Cc:Subject:Date:Reply-To; b=P94d+vLIWcuJoX/nvMlaABWIggWqwMtULSJerQxp/2xnZzfoOxvBP+AqJDW/yMXFd p2pEM+IhnI2FnrK+BXX2urRHypFNmlH4H2b8oS6W58X2bAjV+fZRw/FyTkU3LUMLle ciKjrU21xBPOavdXsqMcrxocKK3ULZHT4ikXiI4Y= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-99072: ipv4: stop route notification sizing when nexthop group shrinks Date: Fri, 23 Oct 2026 14:21:14 +0200 Message-ID: <2026102334-CVE-2026-99072-ef2f@gregkh> X-Mailer: git-send-email 2.56.0 Reply-To: , X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3027; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=9Kf30ldnomONVWHrs/3FuLIaNMhe6jZVyTkxvqmkT0g=; b=owGbwMvMwCRo6H6F97bub03G02pJDFm3A65J1upst2vK9hDs6753ZarhrUW8S7OOiHy1TCpaO M10qQhfRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEzkbTjDPNOT3UWLg0RjPq19 Oy8/o3c7zyMpFoYFLREGG5dYbOT5KnPkS/o1HX/Vwpn5AA== 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: ipv4: stop route notification sizing when nexthop group shrinks Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware flags are changed") added an RCU-only fib_nlmsg_size() call for asynchronous hardware flag notifications. fib_nlmsg_size() checks fib_info_num_path() before each iteration, then fib_info_nhc() independently reloads nh->nh_grp. If RTM_NEWNEXTHOP replaces a group with fewer paths between those loads, fib_info_nhc() returns NULL and fib_nexthop_nlmsg_size() dereferences it. Stop sizing when the indexed path is absent. Nexthop groups are dense, so the current snapshot has no later path. The Linux kernel CVE team has assigned CVE-2026-99072 to this issue. Affected and fixed versions =========================== Issue introduced in 5.12 with commit 680aea08e78c003292415518ad270bc20f9c80b1 and fixed in 6.6.160 with commit 72d9d17092bb37b0717f12042a0817d01a1f9e78 Issue introduced in 5.12 with commit 680aea08e78c003292415518ad270bc20f9c80b1 and fixed in 6.12.113 with commit ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54 Issue introduced in 5.12 with commit 680aea08e78c003292415518ad270bc20f9c80b1 and fixed in 6.18.57 with commit c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49 Issue introduced in 5.12 with commit 680aea08e78c003292415518ad270bc20f9c80b1 and fixed in 7.2.11 with commit ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88 Issue introduced in 5.12 with commit 680aea08e78c003292415518ad270bc20f9c80b1 and fixed in 7.3 with commit d3daa33c7af92e38f2274bbd2576f58bfbaf89e6 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-2026-99072 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/ipv4/fib_semantics.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/72d9d17092bb37b0717f12042a0817d01a1f9e78 https://git.kernel.org/stable/c/ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54 https://git.kernel.org/stable/c/c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49 https://git.kernel.org/stable/c/ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88 https://git.kernel.org/stable/c/d3daa33c7af92e38f2274bbd2576f58bfbaf89e6