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 176B7585992 for ; Fri, 11 Sep 2026 20:00:04 +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=1789156812; cv=none; b=L19erjT4Xx2pQ9grkuw8bug2KNDSX7NK+RXooOJYOyP9Slz/N1OvI8tqdT20mTHy95ZdMTan3RfjHJdhdMGWQJDe+xlr2VUys1AHuW/d1ApqOYKqXWkmaPdQ/fpFCwruUFt6INmg/de732HiV0on9V+F9vH34voeOQmHNvtz1qQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156812; c=relaxed/simple; bh=Q5cVc9FxIwrx5I/J1WCHQa/ZU1Ss1i+VWXioalLljWk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=edjfJS7EjoTI+asewqQnzuZaRbS92O8IByzelRbM9s3t6nPzrLRl0bKX5JsspmHM3KiGGM3Bh/GzluWQKxVc/dofAxMynCYjw9kjWSk04WisIuApcqg9jU1M8e3Ca8PBilgLu7Y+XVqspo13WhT+H4inQOZK8vcKd17Wrp5MnmE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VM4WmxGn; 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="VM4WmxGn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EBDC1F000FF; Fri, 11 Sep 2026 20:00:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156803; bh=F4wWK07E0Lo63ZM56KXgYq6aoKb4tzUkauhhbD9wsDE=; h=From:To:Cc:Subject:Date:Reply-To; b=VM4WmxGnCR8pb5mqYDhqVVfvqQ9RlTMM6mXC97jkMSN1HY7pJX6de4O1wkGquRSH0 VNB2CAh6molC4641gan+AaG0rdQ3xjvzcC02/9XSkGPa9J7/afrJhCqcN2JM3e6FMv ijxB0rMNdqKnVm/aLPRU2ciUBMhuihUlFohAqmtc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89639: cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC Date: Fri, 11 Sep 2026 21:45:28 +0200 Message-ID: <2026091141-CVE-2026-89639-ae1d@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=2845; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=ZNlgobkBhZ26/Z6aoQ3GA6lDpX3gQ2sajv1sFAG7fjU=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIkuT5jNUbl50xS415n5W7O5PyzK7eES/LdiZ8Sfl+ xw9a/9LHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRZb0M8x32Zb/pj1tqrfq7 dMF15dMbmrkPyTIs2LbTlcltv3Rqz2KR7W5zGT2cV7nyAAA= 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: cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC cifs_do_truncate() is invoked from cifs_open() without i_rwsem, so it cannot use cifs_resize_file_locked() to perform a proper fscache cookie resize. Instead, add cifs_invalidate_cache() after cifs_setsize(). cifs_invalidate_cache() calls fscache_invalidate(), which works without holding i_rwsem: it unconditionally increments inval_counter and sets FSCACHE_COOKIE_NO_DATA_TO_READ, ensuring that stale cached data is not served once the cookie is later activated by fscache_use_cookie(). Truncation to zero leaves no valid cached data, making invalidation the correct semantic here. The Linux kernel CVE team has assigned CVE-2026-89639 to this issue. Affected and fixed versions =========================== Issue introduced in 6.18.44 with commit efbcecdecefc26fa062c0e8210533ccad7d6bd4a and fixed in 6.18.50 with commit 8b9b10fe5b8b492b27b9f4546742ea541a650213 Issue introduced in 7.2 with commit fa724e235cfdb0fb0bb427d0f9dfe864ae27403e and fixed in 7.2.4 with commit 81fc3868a7f726980ff845c1d0d271051e5f0f45 Issue introduced in 7.2 with commit fa724e235cfdb0fb0bb427d0f9dfe864ae27403e and fixed in 7.3-rc1 with commit 364b183230586a62660a7280c1eb20138338eeb5 Issue introduced in 6.12.105 with commit 6838bcac954487cc0a3c8a4ee1b3a3a30e244dc9 Issue introduced in 6.18.51 with commit 75640976cf474eb41682a13f2dbe9534ac26ca50 Issue introduced in 7.1.8 with commit 3513f3931c579ba2a715784c6dedc59e0d9282ee 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-2026-89639 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/smb/client/file.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/8b9b10fe5b8b492b27b9f4546742ea541a650213 https://git.kernel.org/stable/c/81fc3868a7f726980ff845c1d0d271051e5f0f45 https://git.kernel.org/stable/c/364b183230586a62660a7280c1eb20138338eeb5