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 F1EA53CFF62 for ; Sat, 22 Aug 2026 15:38:49 +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=1787413131; cv=none; b=Oz1/oJLVoL/cD8r/NEco6SncyvmtecJOt+IUgmFBG5Pl1RUnuCi3Stm90I7QR4OVbt4QeLF4Si/wrC2QyL9Wd+ewb7wj23lfNABZZzmm/ZH3J3hCcaQ2YyYyRloPZOqIfHa6QaluFNoQbt0PTBLY0ulk27Efi/h0IhCXw0i6v8M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787413131; c=relaxed/simple; bh=IysKzsUqyfjjCXdxA1KHhD2hLuhEhLzQLDy7ZV4nepI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=LCMaLbz0DGItNbKzLGOYFsjS7CGnwum3EebficQWnxetuXC6qbsj4I5n4HQ3egh5EIuATIaznSLtIW1r9FNKZ7DtN7ZXypyFxyUbbR187PgIMnHBTW/+89N8yA6gZTZToqHnlIVhWL2F/zbg37TsOHPogyMg3Pf29cSHM5ZQgM0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UYCwZmdE; 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="UYCwZmdE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3C3D1F000E9; Sat, 22 Aug 2026 15:38:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787413129; bh=nmwTSkxUh2iFbqZxx2hoXLoTcpOKD9ILraxPZHR35/U=; h=From:To:Cc:Subject:Date:Reply-To; b=UYCwZmdEKPF9KhAoMsv9OWZv1how7ACbg2qalqekRwr4DqxO2ubmD2bIkyoDxhIys TX0i98FpibiSZopcXK02r6bUIub7W7JqyqzZfukivKijWwPklQMDBByAfj6qBcvZ6U kk9zW4fCENX9PpkNPt72ow29eTppfk6PA/zh07cE= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74695: netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref() Date: Sat, 22 Aug 2026 17:32:59 +0200 Message-ID: <2026082234-CVE-2026-74695-dd6d@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=2923; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=inpvLLLUssqgafgEBk3czDd2xTpWoCMP5YzLAIfDP0o=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmdB659r57PvKHOlsU3QPuT24kH5ptXf4uxnWTxW/3Op fojn8R+dMSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBEOsoYFmz6dcnH9OaWtB3S DP/MuLyuvGL4+ZJhfqDeIbnwr3q+vK+8GV3TPfdOSODcDAA= 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: netfilter: nf_flow_table: drop existing skb dst before skb_dst_set_noref() Incoming skbs passing through netfilter flowtable offload hooks (or XFRM offload path) might already carry a ref-counted dst_entry assigned during earlier RX or routing steps. Calling skb_dst_set_noref() when skb already holds a ref-counted dst overwrites skb->_skb_refdst, leaking the previous dst_entry reference count and triggering a DEBUG_NET_WARN_ON_ONCE assertion in skb_dst_check_unset(): WARNING: at skb_dst_check_unset include/linux/skbuff.h:1170 WARNING: at skb_dst_set_noref include/linux/skbuff.h:1234 WARNING: at nf_flow_offload_ip_hook+0xf6c/0x2b60 net/netfilter/nf_flow_table_ip.c:864 Drop any existing dst_entry reference with skb_dst_drop(skb) before setting the non-referenced flowtable destination. The Linux kernel CVE team has assigned CVE-2026-74695 to this issue. Affected and fixed versions =========================== Issue introduced in 4.18 with commit 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 and fixed in 6.18.45 with commit 12afa450a6a6c0cce2c42b7545a9958f62d8a00c Issue introduced in 4.18 with commit 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 and fixed in 7.1.9 with commit 538e67e8c7889cf5f93951f5309d1bcb41f86036 Issue introduced in 4.18 with commit 2a79fd3908acd88e6cb0e620c314d7b1fee56a02 and fixed in 7.2 with commit 8aecf0bbcc72605592134c917c222207d8f63ab0 Issue introduced in 4.16.15 with commit b4b1adf2e66ecc7125c4117e7aad9ff61e2cfd27 Issue introduced in 4.17.1 with commit 209dedf806d31095968f54323dbe62525b077b33 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-2026-74695 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/netfilter/nf_flow_table_ip.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/12afa450a6a6c0cce2c42b7545a9958f62d8a00c https://git.kernel.org/stable/c/538e67e8c7889cf5f93951f5309d1bcb41f86036 https://git.kernel.org/stable/c/8aecf0bbcc72605592134c917c222207d8f63ab0