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 9CFEE4EC668 for ; Fri, 4 Sep 2026 15:56:58 +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=1788537420; cv=none; b=rIZaKFh0rEqynAe/26vKyibrtAhysFOYPwuDvol59qefBDqOS2Fu4RsllkPh+1ypCUGjgj3q1C//85ba59FXc32I+EKGKxD/CKB133QdhWllSO70zsQrK/pE/C/2Zv1cZtkJ90FeJMdeiPE+wuzHsci/L83Cav0DjsY8h+xfCWM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788537420; c=relaxed/simple; bh=nT6LbovIwSkWlLrm3Y8fjtXwuEZ9duymrjyWbO/EZv4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=i4/DsrYjGByO3MAxpx62/imwPnkOUG1NBpwt2EwSbZf86V3fHQQ5aXk4tQeOi/dfp8AIn47K33RrgqbM6OKR7HDqZhMXe5Yltf43EtHzI+7EsQzFmrjG4dO/mF+pjwNQ9T6zkZH96KCu4VqBvQQxEnowhrleq38mX3TWr4YjKO0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=i0T4OhnF; 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="i0T4OhnF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 527CF1F00A3D; Fri, 4 Sep 2026 15:56:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788537418; bh=+waEUqaot+KTJaoa1CmMhB/M0+L+9Du3o6BFwJMi79U=; h=From:To:Cc:Subject:Date:Reply-To; b=i0T4OhnFHq+sSlGkZVVNIY+MGLuLf5WzKuEfvb5mz0HPdPnZ+ga0I0T2LiMOSwBBJ g3FankZ8DIlL1P/VW2IRaHDrZwvQTRGQgkNoyeFjI5OmR8E2320geBG2Kkm40iVlGU Qqc0muHth/tXI4fvXPlxx77aNx5QWoPygGXFmX9E= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80824: usb: usbfs: fix use-after-free of usb_device in usbdev_release() Date: Fri, 4 Sep 2026 17:52:51 +0200 Message-ID: <2026090451-CVE-2026-80824-055e@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=5165; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=xG4ZrOZhIAYF46kDn4oT1JMyhaYnmPYVIcfmWR7SpGE=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmzXgY/PuP4//P+H5PfL2bgvpn9wPjv1Mwso9iHDfuXi ocsODtRtCOWhUGQiUFWTJHlyzaeo/srDil6GdqehpnDygQyhIGLUwAmkuLLsKDJzfbvdjZ/z5+r dhoYZl2Xb2oMEGaYp8yeXpTCJcOQbXqHN9m5NYLH99t5AA== 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: usb: usbfs: fix use-after-free of usb_device in usbdev_release() usbdev_release() drops its reference to the struct usb_device before draining the list of completed async URBs, but that drain path reads back through the same object: free_async() calls dec_usb_memory_use_count() for any URB whose buffer came from the usbfs mmap() region, and its first statement is bus_to_hcd(ps->dev->bus). After a disconnect the usbfs reference can be the last one, in which case usb_put_dev() frees the device and the subsequent loop reads offset 80 of freed memory and uses the result as a struct usb_hcd *, which hcd_buffer_free_pages() then dereferences. This is reachable by an unprivileged process that has read/write access to a /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the mapping, wait for the device to be unplugged, then munmap() and close(). It reproduces on every attempt rather than being a race, because a live MAP_SHARED vma holds a reference on the struct file, so usbdev_release() cannot run until the last vma is gone and the freeing branch of dec_usb_memory_use_count() is always taken. BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410 Read of size 8 at addr ffff8880122ee050 by task poc/769 CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G B 6.12.94 #3 Call Trace: dec_usb_memory_use_count+0x3ae/0x410 free_async+0x2aa/0x4f0 usbdev_release+0x375/0x460 __fput+0x3ea/0xb50 __x64_sys_close+0x86/0x100 Allocated by task 11: usb_alloc_dev+0x55/0xd90 hub_event+0x2524/0x43d0 Freed by task 769: kfree+0x121/0x360 device_release+0xd2/0x280 usb_put_dev+0x23/0x30 usbdev_release+0x2d8/0x460 Release the device reference after the drain loop instead. Nothing between the two points requires it to have been dropped. The Linux kernel CVE team has assigned CVE-2026-80824 to this issue. Affected and fixed versions =========================== Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 5.10.269 with commit 0a960b88c5979f853019d4dc4957dfbeeb193440 Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 5.15.220 with commit 96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 6.1.187 with commit bd4bffc621a8cb2f4d9ed9b6447415de524a3bef Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 6.6.156 with commit 65879e0a452ca2a234b9475e0c11aff7a4343738 Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 6.12.108 with commit b3cde26a66b04f1d90ed0b675899c88b4e49d424 Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 6.18.49 with commit 5f08c45bdcfd28d1171de38c5ef29fc89a76eedc Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 7.1.13 with commit 7f0278e474c4d1c4457974ff1137cc385c944ab3 Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 7.2.3 with commit 47a7f98fbb5006d46d15a3a210ffdc61448a4f19 Issue introduced in 4.6 with commit f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 and fixed in 7.3-rc1 with commit 0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671 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-2026-80824 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/usb/core/devio.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/0a960b88c5979f853019d4dc4957dfbeeb193440 https://git.kernel.org/stable/c/96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf https://git.kernel.org/stable/c/bd4bffc621a8cb2f4d9ed9b6447415de524a3bef https://git.kernel.org/stable/c/65879e0a452ca2a234b9475e0c11aff7a4343738 https://git.kernel.org/stable/c/b3cde26a66b04f1d90ed0b675899c88b4e49d424 https://git.kernel.org/stable/c/5f08c45bdcfd28d1171de38c5ef29fc89a76eedc https://git.kernel.org/stable/c/7f0278e474c4d1c4457974ff1137cc385c944ab3 https://git.kernel.org/stable/c/47a7f98fbb5006d46d15a3a210ffdc61448a4f19 https://git.kernel.org/stable/c/0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671