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 804A458F076 for ; Fri, 11 Sep 2026 20:01:31 +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=1789156895; cv=none; b=h65JC+GMErdq91L5FNPqrMrf54NwtcwoD1dp+Nn5ThdaP4OE4Ubi2BIU50aDGO+An0kQEhV8oMg6dEJzIjWxLUAxV6oxvB9uHksJoAWrIALI2R3idQ+p/gvwNa3MGN9jJjPFGJSKuPcLctdhCkJ+odeUfE/WMFWg/xucwt6W+4k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156895; c=relaxed/simple; bh=vVpMK/9IeMlgfHmrJStqBuVLzn3dhwfxulYrYwdwd1k=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Yqt/rPtaiw7tE/ys9XxBO6TouqETmhh8lJzFwwPSVFsiBCF+HbVQyKOyR73gHfc+lBwUOmuyfp7aQRdZgWKMTLjyTDPayBmpSMxTm9+ZlfyarEv3xlR/Oa5dnLJy57HzzFhmRwLXHRAWgoYnPlUg1l3NRBNxq6JGCr7QmiJ5U/c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EIn9n4uR; 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="EIn9n4uR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FA031F000FF; Fri, 11 Sep 2026 20:01:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156886; bh=0l+qXcbT7BaejXOn8SRuz6j/oDLN68CCNABuH1Ly79U=; h=From:To:Cc:Subject:Date:Reply-To; b=EIn9n4uRHs5nlTgkinn+A+WkxWXtH+vShZorv2brBlEt1og9vws7xm5VtLkxU+XAc RHEVNYdahpmiSGlCTcimwCK+oPpF+PDOs3W2UZY/VUIcyBqX8pmgZDxjAMhOcfmUiH UVKajv/2fPf2zqb0AV7kO4E4bZr4BCGmpkCVMWtk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89630: smb: client: restore the data_offset bound in is_valid_oplock_break() Date: Fri, 11 Sep 2026 21:45:19 +0200 Message-ID: <2026091139-CVE-2026-89630-1f87@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=2611; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=mlxKpmAMjjr4DppEZw986k6XEb/sxHANzsxbv3n1Dao=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIot33ZPOnbNon//OWy+7C86+XHmKx9tgpU1ktpuZ5 YSLlTpiHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRq20MCzaK/0sTnLF2ifXb r/tfZHO4qKbUyDHMlU+peB23YZnhT75jwr/ey3l+Z/58FgA= 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: smb: client: restore the data_offset bound in is_valid_oplock_break() Commit 83bfbd0bb902 ("cifs: Remove the RFC1002 header from smb_hdr") changed the quantity this bound is measured against. It used to be srv->total_read minus the 4-byte RFC1002 preamble that total_read then included, so it was the SMB message length. The same commit stopped counting the preamble, and the mechanical substitution to srv->total_read - srv->pdu_size left an expression that is identically zero: standard_receive3() reads MID_HEADER_SIZE() bytes and then exactly pdu_length - MID_HEADER_SIZE() more, adding both to total_read. len is therefore 0, the subtraction below it wraps, and no __u32 DataOffset can exceed the result, so the check from commit 097f5863b1a0 ("cifs: read overflow in is_valid_oplock_break()") no longer rejects anything. Use total_read, which is now the message length on its own. The Linux kernel CVE team has assigned CVE-2026-89630 to this issue. Affected and fixed versions =========================== Issue introduced in 6.19 with commit 83bfbd0bb9025f98fa62b44f93bd67466773d1db and fixed in 7.2.4 with commit 5b16a1967a01ad4496a7206a87c3eb16f1df2b05 Issue introduced in 6.19 with commit 83bfbd0bb9025f98fa62b44f93bd67466773d1db and fixed in 7.3-rc1 with commit ba22f575de9deeae4ae0859ca4315a7698226237 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-2026-89630 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/smb1misc.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/5b16a1967a01ad4496a7206a87c3eb16f1df2b05 https://git.kernel.org/stable/c/ba22f575de9deeae4ae0859ca4315a7698226237