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 488073EB0FB for ; Sat, 15 Aug 2026 12:29:02 +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=1786796943; cv=none; b=goHAhDm/awaMA9MDmXaFjt3XGkqMaYzOZHKm0IFIocdFCpt4qjGz3oSHuUKmZEriY/efGbTc1JZedqFqBmJln4xz/pQ8Quj6uDiVWqZH1AcYWLO35KSPRbRWrPbGFa6t7qNyEx+gKTXcWybogq51SOqTn+MDuSYYuoP3y5VGGYQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786796943; c=relaxed/simple; bh=se9CYOnKHUc5xHm4yUy1J34sFcKuY+EBCKl68MHg1H8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=bbjYD5FjCDTQ3vrWVNiQnPxweZOQwgt6fWZzjwXabgoKkD3sS8g/ekePoPckl2WmVlCmYKK8/3/iXi+5qHKWwTDwee6/cfIVg3bV+zZJUPutzBXbZVlHHQH7Rp91A5AbB/AXkv8fnW+lJ3HGvcyHEInMWf635AtvPe4WzyAe0SQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ufqRREHU; 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="ufqRREHU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A02991F000E9; Sat, 15 Aug 2026 12:29:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786796942; bh=ExfckLuzxZCJ/tqVDVlELXKJnGa6Axz0vUWrj68Q35Q=; h=From:To:Cc:Subject:Date:Reply-To; b=ufqRREHUaYBw5GkmlY3b36YPu/qHLasyV0xuPuk2oxsI10kyd1S98eGX6X47dkv33 /lufsolXtXKtDGwdkrY0kwA56fc1jErtZcXjSihJyubdzmMVEVeACKfK90tqQk2iyN Ks2GkMUMRej4PiNvBBm6kTgeyipblsPJ1f6k1Du8= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74476: veth: convert frag_list skbs before running XDP Date: Sat, 15 Aug 2026 21:25:57 +0900 Message-ID: <2026081535-CVE-2026-74476-c830@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=3071; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=17Uk61awKN/eTfgN+Lpkka8WfPKrTdctrXFcrXH5sI4=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNUftjjXZ5lOzMefGno/v0ugt380pafA8b2LkvDO63e 2zLHvSoI5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACZS6c8wz06y7aTbHOFmTle5 iavWf0vL6vxaxbDgsuq1DbOuHPjavFI62cLk7gKe4/IPAQ== 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: veth: convert frag_list skbs before running XDP A frag_list skb can reach veth with data_len set but nr_frags zero. veth_convert_skb_to_xdp_buff() only converts skbs that are shared, locked, have frags[], or do not have enough headroom. It later uses skb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and xdp_frags_size. That exposes frag_list data to XDP as if it were stored in frags[], but frags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment metadata, walk an empty fragment entry, and crash in memcpy() from __xsk_rcv(). Route non-linear skbs through skb_pp_cow_data() before exposing them to XDP, and only advertise XDP frags when the resulting skb has frags[]. skb_copy_bits() already handles frag_list input, and skb_pp_cow_data() builds frags[] output with skb_add_rx_frag(), which is the representation XDP multi-buffer expects. The Linux kernel CVE team has assigned CVE-2026-74476 to this issue. Affected and fixed versions =========================== Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 6.12.103 with commit 5c1c15c540fc45820ce3033c319151ec891bc10a Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 6.18.44 with commit b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fb Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 7.1.8 with commit f9c1fff857e93be709c8b52ed1a643f37bd82c66 Issue introduced in 5.18 with commit 718a18a0c8a67f97781e40bdef7cdd055c430996 and fixed in 7.2-rc6 with commit d0d6415963040c401e7a7e4e482a698ba52448cb 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-2026-74476 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: drivers/net/veth.c net/core/skbuff.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/5c1c15c540fc45820ce3033c319151ec891bc10a https://git.kernel.org/stable/c/b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fb https://git.kernel.org/stable/c/f9c1fff857e93be709c8b52ed1a643f37bd82c66 https://git.kernel.org/stable/c/d0d6415963040c401e7a7e4e482a698ba52448cb