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 DCF78492E20 for ; Fri, 25 Sep 2026 10:29:22 +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=1790332164; cv=none; b=Fiq+vgbJ94CpypjqcyJgWtZIKK1J91FFTgt52FT+Ep1kAco3WzYnQuZiS2Mu5+S+vlJVhIYs9IQAIbj6tceDXUeY5KI2Th3lHMA1FlDnLBuWexj8U6HDbnYZvNC96qr6xmwlv4X4KZtWSJjIg3jQDPI7Eyi5i7WuVz15zp4sH0o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790332164; c=relaxed/simple; bh=pIvqT/ssfg4eFzTqSuxv/0OsKEzWoHcyTRxfdJSUUTo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=VNPNsS5AEazwY6qq6Laz/fmQFl7t/SPq4yENOZLgcxgOmyT+mabaChLthzKtCwl3jy32Hk3crillS8ctziiEJZ0JABz8W2kk/gzsJiFuH6jd2sB3pnK2rib59fK5WkqbzhokN4M8k9QX5LUbj4fbC7ylIFcun8Ip4+essDFhgTs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IIaIlb1q; 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="IIaIlb1q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40A181F000FF; Fri, 25 Sep 2026 10:29:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790332162; bh=CeVDhIfJjBaXjwYa6Wvq19FAwoalWqQHHORskVXYYtg=; h=From:To:Cc:Subject:Date:Reply-To; b=IIaIlb1qnPSQzbX9fVO88gfppl3d6wsWoSu4u1CWsQEGQeFA1u+JXEtSdKCu54fWx QZiTijqE2Y0rdm2EvRiteBXJf2xPRQ7nqfEpzfOZu0oYfmQXsJeUNbRX7Ni2PNc+f6 Rb1aXbloCdLhgMsgHVu+1fJj9Ao9ZAflijBfGJ+s= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-97939: ipmr: account multicast table and route memory Date: Fri, 25 Sep 2026 12:24:02 +0200 Message-ID: <2026092511-CVE-2026-97939-ea2d@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=2841; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Qgc+QQm6NOaVvL/5/K6FhBIG+2gg7jMF+akgPLRANhI=; b=owGbwMvMwCRo6H6F97bub03G02pJDFnbvIODNjxr51TiFHn7wHCpWHW+4yGVx11FT74tmZZhw H71ka5xRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEzkKgvDfAdPwy8LSw8+j7dQ 7/zp/3vC7q73LxgWNGW7nT53PP6p6hpfDe+J185tLLRsAgA= 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: ipmr: account multicast table and route memory A netadmin in a user+net namespace can create many IPv4 and IPv6 multicast routing tables with MRT_TABLE and MRT6_TABLE. Each unseen id allocates an mr_table via the shared mr_table_alloc(), links it into the per-net list, and leaves it until netns teardown. Those objects were not charged to memcg, so the host unreclaimable slab grows with the table count. Account mr_table allocations with GFP_KERNEL_ACCOUNT and mark the IPv4/IPv6 MFC caches SLAB_ACCOUNT. This matches the established handling of IP addresses, routes and alternate interface names. Unresolved MFC entries are still allocated from softIRQ with GFP_ATOMIC and are not charged. They expire after 10 seconds and are bounded by the socket receive queue; see commit 0079ad8e8dc3 ("ipmr: remove hard code cache_resolve_queue_len limit"). The Linux kernel CVE team has assigned CVE-2026-97939 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.35 with commit f0ad0860d01e47a3ffd220564c5c653b3afbe962 and fixed in 6.18.53 with commit 0264b3ee09b118fec8a5471b4ca288f8ab84722f Issue introduced in 2.6.35 with commit f0ad0860d01e47a3ffd220564c5c653b3afbe962 and fixed in 7.2.7 with commit d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c Issue introduced in 2.6.35 with commit f0ad0860d01e47a3ffd220564c5c653b3afbe962 and fixed in 7.3-rc3 with commit b7ee18725f2292ab554aa96a101ae42d45f008bd 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-2026-97939 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/ipmr.c net/ipv4/ipmr_base.c net/ipv6/ip6mr.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/0264b3ee09b118fec8a5471b4ca288f8ab84722f https://git.kernel.org/stable/c/d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c https://git.kernel.org/stable/c/b7ee18725f2292ab554aa96a101ae42d45f008bd