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 8A613541E67 for ; Thu, 17 Sep 2026 16:41:16 +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=1789663277; cv=none; b=sRJLUfStL1QrWMZz6B+csLSSMalBr0xzInv4Fuh0diKE0vJsBmnrk4RbZhpzMwL0Ua20YFMvpjwKJLXyJLQFZYwNxDBY3nlT68OBgox//Zq1fvEPgvmdTTvx2QNGRxtPWx+/62iwqBTtvFdkFAJ9bo3084RxxZWQAUCQg6sOBj0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789663277; c=relaxed/simple; bh=rt1ico77qoNRXKWBSN2h+9khYlC2F4oJ44w2URGnxqQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=F4ZesCPgnVzdVF4LE0i3F8YS5DAxDtILk6D5cO769ToBfi5YZOYANzntYHQXUvFYhZ//l4upuvnCjCnM94u44l5/bBBgPJh0JUquWwUOySB5NZyQTF9uutFSB+G7hanw+6jUxBwAKBa/tLrAIFX/O7WmGF62Cm72GCPoBFtMUk0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Y4nKsyXQ; 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="Y4nKsyXQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC5851F000FF; Thu, 17 Sep 2026 16:41:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789663276; bh=QwK4aSHxnISYjzaU/4+iWbrOdApVWv2TJMVrRgu/NHU=; h=From:To:Cc:Subject:Date:Reply-To; b=Y4nKsyXQHlv28kUWnJF/eRBKeyiJ7tYvURPiWJiYpezxQuIbEEWHI9OE2tVq06B5Y SgASFA1Omumwyc5JSXvpEcZJIVAAXJI6q5nU7TBoMjpwXtOK7UQATNt/4BAyeV9+Gr 7TAa1Ql1SCwK1S+tlwtkpHKD5yQESfZtlo94p1rk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-93186: cxl/mbox: Clamp mailbox output allocation to the payload size Date: Thu, 17 Sep 2026 17:17:43 +0100 Message-ID: <2026091703-CVE-2026-93186-a366@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=2749; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=kjIIqDHBqphc/+TkdAQKDRiDAgbD3peGPjDKxwLhduo=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBG5P98ztySwWz7D4uV5g89a7PotnyKfn1z3n1pD8J BMUVejXEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABOJeM4wP8tdioF75lmGGZvj lB4/U+8sKJBdzzBP5/7iab5/tbRbZicsb0z8/+ha6iNuAA== 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: cxl/mbox: Clamp mailbox output allocation to the payload size CXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload size but leaves out.size unbounded, then cxl_mbox_cmd_ctor() calls kvzalloc(out.size). A large out.size drives a huge allocation, above INT_MAX it WARNs and taints, and with panic_on_warn=1 it panics. The transport __cxl_pci_mbox_send_cmd() already clamps the response copy to min(out.size, payload_size, device len), so the output buffer is never written beyond payload_size. Clamp the allocation to payload_size too, matching the RAW path. The Linux kernel CVE team has assigned CVE-2026-93186 to this issue. Affected and fixed versions =========================== Issue introduced in 5.12 with commit 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and fixed in 6.12.110 with commit f5d2bbf0300f46307948864fbb97bce5097f4fe2 Issue introduced in 5.12 with commit 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and fixed in 6.18.52 with commit 31d4841eca7c4b75751ca96d24339e19303337f2 Issue introduced in 5.12 with commit 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and fixed in 7.2.6 with commit b4e11c731d6bee3b87315e055a1ca417c92dc1fc Issue introduced in 5.12 with commit 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 and fixed in 7.3-rc1 with commit 8a13db9f899d149c3aab24abcb668121cfda5a4f 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-2026-93186 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/cxl/core/mbox.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/f5d2bbf0300f46307948864fbb97bce5097f4fe2 https://git.kernel.org/stable/c/31d4841eca7c4b75751ca96d24339e19303337f2 https://git.kernel.org/stable/c/b4e11c731d6bee3b87315e055a1ca417c92dc1fc https://git.kernel.org/stable/c/8a13db9f899d149c3aab24abcb668121cfda5a4f