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 8F7D23EA946 for ; Fri, 11 Sep 2026 20:02:20 +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=1789156945; cv=none; b=n9nFHKxCEfcecDig1tK1WsBcBa4mXGSucyhJ/ZZENT97mf1+Wx2yemLKCyHMrbAHaZQjO510sswgsWHXZ9z8IhMUqjcxXrCl2aXVVmgF5/M7qGdef7dDRNnMO2GnQL2qvdMwgvHAHGkBFrbGE5u/fDosHr2Ein8OqZ9Vj3jZAsw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156945; c=relaxed/simple; bh=ZV5l8GM21yroL//KTXYaMqVTEG3k2/Xs61ZBMZ18s/E=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RpxCbr/paSkbyO8MrlZT6uTeG6yXc1gM8TA2oe6dOADRqBD0XKDJwUPDqbd+POx/eGslaJGynZ5Yd7KGCDErL+wHxPoV1fwRGUhGK62uhKK/y5GbCDnSvcqbz3XXxVIhRbKOMviCR7MCyj0PV4GIIUk24bexBcT+yDcvYJ8ABIs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iqoKZ9+C; 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="iqoKZ9+C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 633B31F00893; Fri, 11 Sep 2026 20:02:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156937; bh=xaI28QRiFDJi2RF3ridhOlAeDhQYvB1WaLR6f4cWJ98=; h=From:To:Cc:Subject:Date:Reply-To; b=iqoKZ9+CgCPjiEyIaJXVl0qwk2642jZPYYRlCeBWVcSpEZKggbUFlLo0ANLQ0MNqV UZuJZrncRDcUyNMwxvluWapHiYwiZlsTg6lbPNzaQrQhr9jLqn+bRwhxctYyP9ya57 w3DFDRYkF0c3xjjaz0yPGgrlijIJTTBejLevBJ5E= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89682: nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net Date: Fri, 11 Sep 2026 21:46:11 +0200 Message-ID: <2026091151-CVE-2026-89682-1079@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=3265; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=M5m/aeX+zzHdCgjTSyD87AEKZt0uHahtjUYoPKaGOY8=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIusz7l0p7DvD/E1anuPcO+624x/5E9PTVO8cvP7h8 ym3kibjjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZiIXTXDfP+aJ+xrPPm7zXwq 1M7KL2RRPn7FlGFB85E195J2uR7/7HuoNadzl7935K1AAA== 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: nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net nfsd_file_dispose_list_delayed() defers fput() to nfsd service threads via a per-net freeme queue, preventing the shrinker and GC worker from bearing the cost of closing files (see ffb402596147). However, the queue lives in a separately-allocated struct nfsd_fcache_disposal that is freed by nfsd_free_fcache_disposal_net() during per-net teardown. The global shrinker, laundrette, and fsnotify callbacks can still be inside nfsd_file_dispose_list_delayed() dereferencing that pointer, causing a use-after-free. Inline the spinlock and freeme list directly into struct nfsd_net (as fcache_dispose_lock and fcache_dispose_list), eliminating the separately allocated struct nfsd_fcache_disposal entirely. These fields now have the same lifetime as the net namespace itself, so there is no dangling pointer to chase. nfsd_file_cache_start_net() now just initializes the inline fields and cannot fail due to allocation. nfsd_file_cache_shutdown_net() drains the inline list directly instead of freeing a separate struct. The alloc/free helpers are removed. The Linux kernel CVE team has assigned CVE-2026-89682 to this issue. Affected and fixed versions =========================== Issue introduced in 5.17 with commit 1463b38e7cf34d4cc60f41daff459ad807b2e408 and fixed in 6.18.51 with commit ba0ee9e04b7a0356c28d5a2fe445db675d24e572 Issue introduced in 5.17 with commit 1463b38e7cf34d4cc60f41daff459ad807b2e408 and fixed in 7.2.4 with commit cadc9036d5a8209f89e7026ddba7cfb1c716b03c Issue introduced in 5.17 with commit 1463b38e7cf34d4cc60f41daff459ad807b2e408 and fixed in 7.3-rc1 with commit bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4 Issue introduced in 5.10.220 with commit e8f923e1e9fcc0832a12c8a2461792e5a9544c03 Issue introduced in 5.15.154 with commit 3bc94fb44f10ef852723e1aeaac6794c5ab16aec 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-2026-89682 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/nfsd/filecache.c fs/nfsd/netns.h 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/ba0ee9e04b7a0356c28d5a2fe445db675d24e572 https://git.kernel.org/stable/c/cadc9036d5a8209f89e7026ddba7cfb1c716b03c https://git.kernel.org/stable/c/bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4