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 99D3958599D for ; Fri, 11 Sep 2026 19:58:07 +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=1789156695; cv=none; b=cSCh3EZCbUA0rhY4/KQNuXJbiPj3PfonVHCUDMvDdFLiXWI1K9kvk8OrIVLhk0KE9tm9b8XsJike/XY+SrjsiK2GW+qJn165OYjbwWyii1VKPHvMJJCRC3Enb0W+8MlQ8Kr6fCsdQIioUwje4QJwdLgK6rA2O4kZJIi2BPhu9jc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156695; c=relaxed/simple; bh=bSZ3NThNWu8BRjfl3Rrq43LN7JJPG2yGUKC4uRvPaf0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=oxN5yuXsvtMr005bxityJ4EAcqwdxfKgLuYAJg4YI8BFpgfPPgiuJdlJxqgtm80k0M7gSTk7O/87GB/XHJ3UaXWuv/8kSq0K4K9AnZ2GNkKWN+w3b5Zym7XU/Q0uNpY9yTYjRWx1eBjjUdPqhmoxoDl9EN0cfWW8WujxBora344= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UvVScrjg; 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="UvVScrjg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C5701F00893; Fri, 11 Sep 2026 19:58:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156684; bh=toaguAuVJgX65w1F+ezv6QeqEEPSbmCA5xdGiB2NMgY=; h=From:To:Cc:Subject:Date:Reply-To; b=UvVScrjg4fWX0U1x85I2lXg/kME8jF8uYoIHIh0iQ59jhtifEaXMS54BFj0e+6rXO J/mKn9hlULktO8DCq4sDb6weMTniZ2LsBlikeAxb34lEeVJrJGB+1MLPk9IzgHeH94 PI+IyNGCgJLADE5NlPgbj2x8VD7H21w1GY7Zm6lI= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89600: fanotify: fix use-after-free of file range info Date: Fri, 11 Sep 2026 21:44:49 +0200 Message-ID: <2026091132-CVE-2026-89600-0dcd@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=3295; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=/XnmKN5HpHahvlveIOTiKQhsZ7oSjb2NUQFkHBSR9Xs=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLInNcwk9yrL0U/H2Ho1eS2y47hcVz1Pf2eB2MWj6P7 YLCpyXrOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAicxYwzJU4sPrt3ZVTezZq /jo7L01Y+tQaoziG+TFRJieDHq65/cXh4uet6gXfMg4tbwMA 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: fanotify: fix use-after-free of file range info fsnotify_pre_content() builds its file_range on the triggering task's stack. fanotify_alloc_perm_event() saves a pointer to range.pos in the heap-allocated permission event so copy_range_info_to_user() can report the offset later. The event reader can set the event state to FAN_EVENT_REPORTED and then sleep while preparing the file descriptor. If a signal interrupts the triggering task at that point, fanotify_get_response() changes the state to FAN_EVENT_CANCELED and returns. This unwinds the file_range stack frame while the reader still owns the event. The reader then dereferences pevent->ppos and copies the stale stack value to userspace. KASAN reported: BUG: KASAN: use-after-free in fanotify_read+0x293e/0x2970 Read of size 8 at addr ffff88811434fc50 by task fanotify_inotif/95 Call Trace: fanotify_read+0x293e/0x2970 vfs_read+0x177/0xa20 ksys_read+0xf7/0x1c0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Store the range position directly in the permission event and use FANOTIFY_NO_RANGE when range information is unavailable. The event remains alive until the reader finishes, so the reported offset no longer depends on the triggering task's stack. The Linux kernel CVE team has assigned CVE-2026-89600 to this issue. Affected and fixed versions =========================== Issue introduced in 6.14 with commit 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 and fixed in 6.18.50 with commit 66aa9a9e6481bfa512ee5b6380eaaec455a954d2 Issue introduced in 6.14 with commit 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 and fixed in 7.2.4 with commit b8f73b163b646bc56d4dce9c697a578e333f4894 Issue introduced in 6.14 with commit 870499bc1d4dc04cba1f63dd5e7bc02b983e2458 and fixed in 7.3-rc1 with commit d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851 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-2026-89600 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/notify/fanotify/fanotify.c fs/notify/fanotify/fanotify.h fs/notify/fanotify/fanotify_user.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/66aa9a9e6481bfa512ee5b6380eaaec455a954d2 https://git.kernel.org/stable/c/b8f73b163b646bc56d4dce9c697a578e333f4894 https://git.kernel.org/stable/c/d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851