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 399D1566C79 for ; Fri, 11 Sep 2026 19:46:17 +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=1789155994; cv=none; b=L0DDNvq9ZoGgi51TO8vPwEi9SB3fBgGJChpUplBvdkpJv9N514+Ez66+Y17EFgOtNVJ69w6jMo2i1dztx673X/M55iOC5UJbnHzdfTTx0eifu4Nh+2ieJEA1HYRWC+0PTPX9UAbrJ1gLIOpOdxD76VJdmAHRA5KQI3iffCVjVSs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789155994; c=relaxed/simple; bh=LygwadtE6uxa0EIyZBhYUCi3E4LwuYb5Whr0hXTxeTE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=TvC+vCa8JDuHWzUfZh9ZA/+Sir75JvKSJYGFLQ45+DE3B33CIDNA0zoWDKJJzsXJx9rzUHNt/TaxzO+ITtiG08yMStEbexmnvENjnnU3gEACXeHlDFyYBGHlnHo4UrKDS6j+IiflwHSoIxOIFdQ7EOCxXFQk702Kp4vDqHlXd8Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TXqJ56R3; 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="TXqJ56R3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 400E41F0089D; Fri, 11 Sep 2026 19:46:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789155976; bh=vb/MUp7Sc9qI/qs7ZRbx0NJmVgkPutedIcTZ2ciq12Y=; h=From:To:Cc:Subject:Date:Reply-To; b=TXqJ56R323WxeP9SWjGQgmMqcURYErOxzZVWRkg5JacVsYT4r/2tx/jlTFUuoAz6U p5c4KZRy3kAAMsTTuC+7GIKHedMYI8n5qpmx7VGRE2vhtLvpNxJcw+4Bf1WaeBZXUZ E7a2ktz9LwN4KYYiWjr5KgLBXo0KwFDO/q6bEYTM= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80946: fuse: copy request headers via a stack buffer for io-uring Date: Fri, 11 Sep 2026 21:40:52 +0200 Message-ID: <2026091138-CVE-2026-80946-c5f9@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=3303; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=pOu5AdpD/BeoY0xX3rgbkFAxCN6vho9vyD5TB1ADB0I=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIs2mzmeZfHXzqT89W36yJLx56LDMklllajOvpN28y wasTyq1OmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiD50YFszOV1wV/r5u6aQG iyMMGlvbHx7uDGGYyZib2uvXUCvzo3/u7UNXLb9dCLxlBgA= 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: fuse: copy request headers via a stack buffer for io-uring The fuse-io-uring transport copies req->in.h out to the ring in fuse_uring_copy_to_ring() and req->out.h back in fuse_uring_commit(). Both headers live inside the fuse_request slab object, whose cache (fuse_req_cachep) is created without a usercopy whitelist, so copying them directly to/from userspace trips CONFIG_HARDENED_USERCOPY and panics: usercopy: Kernel memory exposure attempt detected from SLUB object 'fuse_request' (offset 56, size 40)! kernel BUG at mm/usercopy.c:102! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:usercopy_abort (mm/usercopy.c:90) Call Trace: __check_heap_object (mm/slub.c:8268) __check_object_size (mm/usercopy.c:197 mm/usercopy.c:258 mm/usercopy.c:223) copy_header_to_ring (fs/fuse/dev_uring.c:618) fuse_uring_prepare_send (fs/fuse/dev_uring.c:776 fs/fuse/dev_uring.c:785) fuse_uring_send_in_task (fs/fuse/dev_uring.c:1306) tctx_task_work_run (io_uring/tw.c:96) task_work_run (kernel/task_work.c:233) io_run_task_work (io_uring/tw.h:84) io_cqring_wait (io_uring/wait.c:278) __do_sys_io_uring_enter (io_uring/io_uring.c:2685) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Bounce both headers through an on-stack copy so the usercopy touches stack memory, not the slab object. The Linux kernel CVE team has assigned CVE-2026-80946 to this issue. Affected and fixed versions =========================== Issue introduced in 6.14 with commit c090c8abae4b6b77a1bee116aa6c385456ebef96 and fixed in 6.18.51 with commit 194d0fb0ea4720535ff3168c9d04c7632cec7071 Issue introduced in 6.14 with commit c090c8abae4b6b77a1bee116aa6c385456ebef96 and fixed in 7.2.4 with commit a47a416ff68d706dc3327ab583f86b9ee757358b Issue introduced in 6.14 with commit c090c8abae4b6b77a1bee116aa6c385456ebef96 and fixed in 7.3-rc1 with commit fd10f40af314f07b6d6e028b1ca25c8b49903aab 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-2026-80946 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: fs/fuse/dev_uring.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/194d0fb0ea4720535ff3168c9d04c7632cec7071 https://git.kernel.org/stable/c/a47a416ff68d706dc3327ab583f86b9ee757358b https://git.kernel.org/stable/c/fd10f40af314f07b6d6e028b1ca25c8b49903aab