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 9C3AF58FD0C for ; Fri, 11 Sep 2026 20:02:07 +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=1789156934; cv=none; b=Of+hGRGQHL9Z3Dx5dXEvYcKLTZQV8gqBpNrjNGSLyzOUFEvFRtnlYl489c8O9hPqvlChU13VbsI6jMwuLAieJ3+eBZoKB49Wq5ocJ9NYHBNrI8yO9K1u5C9M/lF4aoRDhMUby1zkg+b3AeITP95Lv6ZoCoi7+zpChuHoN4Em7/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156934; c=relaxed/simple; bh=cYPTQj29CtyLCIiREce6NBxp5z5LbWy2fz3kEBu4pYI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=qAgSVJ4uS8unLIpv7uAd1blBcMNWAN/hJTcOpUuxCBCh0+2G9efHE+KmkunFce7p2tg6WXK6zh0GOb1MtLe5LmmDNu2bgzYGgSbyR8iipDql4znChF6N7FtYAghzb9FXc3r7dUGBmS+LS5Zlgr22vDBJw0tnIjvGLYbwDBfJLh8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rXzQKk8Z; 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="rXzQKk8Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D8F71F00898; Fri, 11 Sep 2026 20:02:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156924; bh=Tx/QbrhgoeloH4tWjXpXugdMBMLn4uEY+MzVBd8hGJg=; h=From:To:Cc:Subject:Date:Reply-To; b=rXzQKk8ZhcmFCt8/BqTLJx6JG6MtWEHEbuafWQtFHlf18KBd2oxHxE1YrkIk1K5Q9 uWBuBlA6ZF85J0H08qUx5+OxuynhWT2uakJr35G55eXKjYLSuV7x59pjJfBEe5TXDn SCuTynYaD1Htyjzz5LOb1b84a4Isbmp3UfOjT9wM= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89679: nfsd: fix null dereference in nfsd4_setattr for deleg timestamp attrs Date: Fri, 11 Sep 2026 21:46:08 +0200 Message-ID: <2026091150-CVE-2026-89679-0f4a@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=3163; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Lap9iNHBY6+1P6AFjkZS4j1ceutkYTmObpyLtyn7Nwk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIuv2vrt74XUL7/lzC9X5w/UZT7Ie7dj1suv8yuVz1 jYv8Jc+1RHLwiDIxCArpsjyZRvP0f0VhxS9DG1Pw8xhZQIZwsDFKQATeS7CMN9DNijuWs75nycT ns2aWGO3WzM4oJ1hwbzI4z1b2k3aygvuNyl+C3y3RmaaCQA= 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 null dereference in nfsd4_setattr for deleg timestamp attrs When a SETATTR request includes FATTR4_WORD2_TIME_DELEG_ACCESS or FATTR4_WORD2_TIME_DELEG_MODIFY in the attribute bitmap, nfsd4_setattr() sets deleg_attrs=true and calls nfs4_preprocess_stateid_op() to validate the stateid. If the client supplies the NFSv4 "one stateid" (all-0xFF bytes), check_special_stateids() returns nfs_ok without populating the output nfs4_stid pointer, because the special-stateid path in nfs4_preprocess_stateid_op() jumps to done: with s==NULL, and the "if (s)" block that would set *cstid is skipped. The local variable `st` remains NULL. Back in nfsd4_setattr(), the if (deleg_attrs) block then unconditionally dereferences st->sc_type (at offset 4 from NULL), causing a kernel oops. This is remotely triggerable by any NFSv4 client: send COMPOUND [PUTROOTFH, SETATTR(ONE_STATEID, {bmval2=FATTR4_WORD2_TIME_DELEG_ACCESS, ...})]. No authentication, delegation, or prior state is required. Fix by adding a NULL check before the dereference. A special stateid is not a delegation stateid, so the existing nfserr_bad_stateid return value is already correct; we only need to guard the pointer dereference itself. The Linux kernel CVE team has assigned CVE-2026-89679 to this issue. Affected and fixed versions =========================== Issue introduced in 6.14 with commit 7e13f4f8d27dc02fb88666f603c53ca749d56f92 and fixed in 6.18.50 with commit 3c5119b799a7f57db332b2c31e806de16c869f0f Issue introduced in 6.14 with commit 7e13f4f8d27dc02fb88666f603c53ca749d56f92 and fixed in 7.2.4 with commit 3c896db123892256fd39af0ee8c2d02c63539983 Issue introduced in 6.14 with commit 7e13f4f8d27dc02fb88666f603c53ca749d56f92 and fixed in 7.3-rc1 with commit fe456c8c0931bb3e8a03d429920e87fd85747fba 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-2026-89679 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/nfs4proc.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/3c5119b799a7f57db332b2c31e806de16c869f0f https://git.kernel.org/stable/c/3c896db123892256fd39af0ee8c2d02c63539983 https://git.kernel.org/stable/c/fe456c8c0931bb3e8a03d429920e87fd85747fba