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 617C14D795F for ; Thu, 17 Sep 2026 16:22:46 +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=1789662167; cv=none; b=f/uxAGY3nehPhYvF5hT5XWK0boJj7kJ8WAfT6K2IUXLdaH//GyMBReswggpUvelaTFxBDw+6vFDpbbWtGGm1dgyMemjfQ07EzsTuP+TFlEr0JDTAvKdpDQYb7xhCJIYQ/jNnwtaelN6/qDYFt8vWqfzydnzdmRZoUFeOhyg3hv4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662167; c=relaxed/simple; bh=oCwuOZ/tuBgyq2KB1VKVnvDo1hrv23xxOQ6Fu+3drMw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=rFMvyEP1jdllzEKC7U2zjgOtuRuSp0HijVAX3cHGCRrvj0YXlZUIICDXmI4mk7M58sLm9H65Y+bn9JyQVDyD/x1b2HuFtYc5LxveGYWnkEZd+bJnCTTMjX/pK2gmy8pwTFAbGCh8WJBulGrTffOjT5RpJfv2b5oOIOiztrw0D/4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ukqWq7nB; 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="ukqWq7nB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C61C1F000FF; Thu, 17 Sep 2026 16:22:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789662166; bh=Qt80TJXDOsgNV2zGz61mCI4rlCoewImk5LJfck5uF9Q=; h=From:To:Cc:Subject:Date:Reply-To; b=ukqWq7nBbyAiFcBnHvMapdSgxwVhx0aRzRNQoxFvqng3ZUT3xt5WpunUgOjgiJ2fG ctme/S8mHG3A/Qb64N7vJtRAW5VJrCV6AzYUFb52UeEp1CSHF0Uc+R0M51FCRPPpuS CbC8WvLPTUTA9LQ5Do7mqV9Z7TsDH3qNCUMNXbxI= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-90263: btrfs: check if root is readonly when setting posix acl Date: Thu, 17 Sep 2026 17:11:33 +0100 Message-ID: <2026091746-CVE-2026-90263-e245@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=2478; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=guOzetYnR5pHVroY+KfVjHMkWqlOFzNKHFm0psMsCtY=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBPo/lz5es7LOxET0ctXtxfuL5f+tlVrBPCtl4xeLr 8fE0lTWdcSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBEJBoY5pmt+C1/WPH0dMHr D39G6In/PfW+jJVhftylV7+43qib2Im8m+W5/sTdimy/DgA= 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: btrfs: check if root is readonly when setting posix acl For a filesystem which has btrfs read-only property set to true, all write operations including acl and xattr should be denied. However, acl can still be set even if btrfs ro property is true. This happens because no function on the set_acl code path checks the root is readonly or not. It was checked in btrfs_setxattr_trans() but got removed in commit 353c2ea735e4 ("btrfs: remove redundant readonly root check in btrfs_setxattr_trans") That commit didn't check if all the callers properly check the root's read-only flag. A previous fix is commit b51111271b03 ("btrfs: check if root is readonly while setting security xattr"). Always check if the root is read-only before performing the set acl operation. The Linux kernel CVE team has assigned CVE-2026-90263 to this issue. Affected and fixed versions =========================== Issue introduced in 5.2 with commit 353c2ea735e4b54fb6250861e67b51b1bcb47198 and fixed in 7.2.6 with commit d5602f96ff1e266f069b4d0d94f441050e057e06 Issue introduced in 5.2 with commit 353c2ea735e4b54fb6250861e67b51b1bcb47198 and fixed in 7.3-rc1 with commit 01c2f41fc441f75b3f9326443372faceb1cb6638 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-2026-90263 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/btrfs/acl.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/d5602f96ff1e266f069b4d0d94f441050e057e06 https://git.kernel.org/stable/c/01c2f41fc441f75b3f9326443372faceb1cb6638