From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B406135F615 for ; Fri, 8 May 2026 07:22:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778224921; cv=none; b=otUxMP4nXEU5ydWIXhTNPNCv5K5FUG7YCPEzkCbMKWIe0cQChhqX/DBJIGczaAxxOxS68KVPft4st0a3W6dV8GZqqiNX/4K5bizPO5SjgzoA4+e3mFfw8MAytN+yywyJuiOhFwy8EFajttb9qNqQFmEsp1yRnRENxP9sW1HIdqg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778224921; c=relaxed/simple; bh=6zWv8mFPC/dP1Qzk/NvvNOorNGFudGqybdoyAGy8PtU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=YX2ig5gKBMc3Ia4RZoq2szCMiVZa5ZcjNJga49KRBViWfn2Qj4gqF08w6frrH4VNtPyOj6VOy8CbdMXvAux2/H794B2gfjpdngT7zlRHmcK7/p9fw2Vga/VVZsv/+hk4c3W2Wuc4a3pcA5AT1K2GE/aJy6rnwcU2qYIMt6d1kpo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BwrG8aFE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BwrG8aFE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A60F3C2BCB0; Fri, 8 May 2026 07:22:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778224921; bh=6zWv8mFPC/dP1Qzk/NvvNOorNGFudGqybdoyAGy8PtU=; h=From:To:Cc:Subject:Date:Reply-To:From; b=BwrG8aFEmi3x8UckDIKCnqjdY2vyi6exeeGpQ3lcLzRXbaCb/BQm4BfXPaV2DLTzX Q3a2AKYp/mnkVS4gAFFmPw9SXdYlaX1kiWE+BiNMgmAh+NLk1bpzydlWijPrD42S6v 2MvvNeFrzBXtuFhshNsENMbDEq8vNvX7+nVnCLhY= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43284: xfrm: esp: avoid in-place decrypt on shared skb frags Date: Fri, 8 May 2026 09:21:57 +0200 Message-ID: <2026050856-CVE-2026-43284-6598@gregkh> X-Mailer: git-send-email 2.54.0 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=3596; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=OflHf60oU49kFdEtPwx8ptvlTlu1TE0jGO2GJmm1gaU=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/+0WKN2+p6TRi6lDzePBLwOfQB80W0fCa9LBP/1S/m MyeOn1lRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEzkeQDDgm2bVs0P1I6YcOJu a9yNrdcqFiyWrGJYsKpkeb3uV7OLey5N+sEX3F30ymbuHgA= 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: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data(). The Linux kernel CVE team has assigned CVE-2026-43284 to this issue. Affected and fixed versions =========================== Issue introduced in 6.5 with commit 7da0dde68486b2d5bd7c689a9b327b77efecdfd0 and fixed in 6.6.138 with commit 50ed1e7873100f77abad20fd31c51029bc49cd03 Issue introduced in 6.5 with commit 7da0dde68486b2d5bd7c689a9b327b77efecdfd0 and fixed in 6.12.87 with commit b54edf1e9a3fd3491bdcb82a21f8d21315271e0d Issue introduced in 6.5 with commit 7da0dde68486b2d5bd7c689a9b327b77efecdfd0 and fixed in 6.18.28 with commit 71a1d9d985d26716f74d21f18ee8cac821b06e97 Issue introduced in 6.5 with commit 7da0dde68486b2d5bd7c689a9b327b77efecdfd0 and fixed in 7.0.5 with commit 52646cbd00e765a6db9c3afe9535f26218276034 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-2026-43284 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/esp4.c net/ipv4/ip_output.c net/ipv6/esp6.c net/ipv6/ip6_output.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/50ed1e7873100f77abad20fd31c51029bc49cd03 https://git.kernel.org/stable/c/b54edf1e9a3fd3491bdcb82a21f8d21315271e0d https://git.kernel.org/stable/c/71a1d9d985d26716f74d21f18ee8cac821b06e97 https://git.kernel.org/stable/c/52646cbd00e765a6db9c3afe9535f26218276034 https://git.kernel.org/stable/c/f4c50a4034e62ab75f1d5cdd191dd5f9c77fdff4