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 C6D9351C321 for ; Fri, 11 Sep 2026 19:49:29 +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=1789156183; cv=none; b=tu0vwS9NSfJcY6HqJSTb90Fixhg7A8mAb9vHfVV/auc9L+4z8eVZZNvWnfToRAT9MwMtyfmBf9W9YztSZaH2bdwXpZch3MynyG4z/NmEbhJ49x8YuKvcx1yrt8FOG0rNEABj43VV9NEPcAEt+yyVjtDziWCGXJMsjvAJMjrTHIw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156183; c=relaxed/simple; bh=aUoXGZZwcvZKsDEBrrM7QNUz+8AYXYEhUvwqJHDPiaw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=sj4S2lwxOSztfU7k3RJZbfXZ3RcCWQ/ex/35mcyhk9Ra/ABYe6/cS7PyjR/rMCaNl+QA7Gq4Ly1hhkqBa5i4tcjRjgx381PcMAjFS32ZhwDTg1aXrfqBiWC9i95d/4RtQ7t5wpFE8gVN/6N9Ibk6C3R6NCTGJ9AEtciBruMwgkI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=efXkCXlB; 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="efXkCXlB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD9181F00899; Fri, 11 Sep 2026 19:49:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156166; bh=VkKIDTMI7+Zbj8V8Atn5qJ1MgAFQEn+XPP4BaWvehPM=; h=From:To:Cc:Subject:Date:Reply-To; b=efXkCXlBR7GQkA5QcTVLi5DXFJu7gt7lgWr3j4L6H1MIi5b+XNq+30TFbLA9dfXeD AoeTbKXWa2mz3Z8ufs02hyHmtVIu266YutddD8d3PUmjsIYJ5xDBa+6VUqL5E6zaYZ M6spM5XPzR+3NZYnCdzqkBHIQqg4IjGcOyCE3yiQ= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-81009: io_uring/query: cap user size passed to copy_struct_to_user Date: Fri, 11 Sep 2026 21:41:55 +0200 Message-ID: <2026091153-CVE-2026-81009-bc08@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=2508; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Z51dJEv5hQ2r/Gi8VVMv4Z0g/q3de8vxLcXPE0+SKkk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIl27HyydcM5UpvZyua7Z50TWyAcH581OfFT/OU782 zEPJiutjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjIaWaGeTp7+P/PDCqclvk4 /m4i21s+O9vlIQxzxQ5LmOazP7z79W/u9N60LW9n5vKvBQA= 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: io_uring/query: cap user size passed to copy_struct_to_user io_handle_query_entry() clamps hdr.size for the inbound copy_from_user() but keeps the original user value as usize. copy_struct_to_user() uses that usize and, when it is larger than the kernel result, clear_user()s the trailing bytes. As hdr.size is a __u32, a query can request nearly 4 GiB of zeroing, including on the error path where res_size stays 0. The interface is reachable without a ring via IORING_REGISTER_QUERY. Reject sizes larger than PAGE_SIZE, as recommended for copy_struct_* interfaces. The Linux kernel CVE team has assigned CVE-2026-81009 to this issue. Affected and fixed versions =========================== Issue introduced in 6.18 with commit c265ae75f900cea4e415230a77b5d152377627dd and fixed in 6.18.50 with commit 417e02f7b6051765b91cf1289071882eebd172e0 Issue introduced in 6.18 with commit c265ae75f900cea4e415230a77b5d152377627dd and fixed in 7.2.4 with commit 2b8ad4981ecedb14c1fdd811ab977010b23933e6 Issue introduced in 6.18 with commit c265ae75f900cea4e415230a77b5d152377627dd and fixed in 7.3-rc1 with commit ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b 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-2026-81009 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: io_uring/query.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/417e02f7b6051765b91cf1289071882eebd172e0 https://git.kernel.org/stable/c/2b8ad4981ecedb14c1fdd811ab977010b23933e6 https://git.kernel.org/stable/c/ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b