From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792758710; b=rk3IhmHmJKwwpaPvQRX00MV0mnNgus1ZItlGjGimWoUCK1xYyhZL0tcz0ALnLs1BT4mH wibkqkUGQ9tj+55f/8rRTiKnMF8YpupXL9DPh5ZIwG5a7MVTgHZVnSwmRkfTbgXCP0eyY J+IqHD6ZJq88y+RAxrc+mBW3YjqJf2hbbrmhYpduRGRV9CHym8jqX+doqyjkZYQyTtO5Z 6/xbqrgobo/Y8qKC2u8ig575RvGRky5+8/6itcMbCnLsY+s56tAH5mtLKnRX3X5m+Oqn7 gkhc2oyW3wn6gfPs5Eh3+aAXnmygq5YkSf/Y/oRMMrhl9ZtfbPL4dc1Bl3lwVxGS6aA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792758710; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: Reply-To:MIME-Version:Lines:X-Developer-Signature:X-Developer-Key: Content-Transfer-Encoding; bh=+hEGuN7L33nzqNrkW1R1sp/9yzqapFv4Xx+7CsNT3q8=; b=FFNeorLdy4DeZEBjQvPICE5Lus7s2RMuUkGyIgBcq/gGaYgiC29XU9gwBaBnjbSFsgTI gw0jzBEvcD2eIha0LSgK4+8fTcagPe+KXnc2ahLnXEBjV8bPIW0/36MsOS860T0wGgoyK TO05yzrRwYIPD6KYLFVGrm4oUqeK6Buasv9JQqwu17k3pto1qAMiIUYBziLFrBhcwNkhv I3J4agJ59fPrd939Z1LBcOsgSNrPt2Ncpd9E49No9B237qKSV/9QD5H5B+YCmMN+SjZEv tcdQGHdOyg549fTcajLbBW8IRwLbRJ+6q4IyAYNU3P8eiUvZvkGfS+u+tEbxpfIY5GA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=I1W+4uqB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D25B7606A31B for ; Fri, 23 Oct 2026 12:31:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=I1W+4uqB Received: by smtp.kernel.org (Postfix) with ESMTPSA id A90461F01825; Fri, 23 Oct 2026 12:31:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792758709; bh=+hEGuN7L33nzqNrkW1R1sp/9yzqapFv4Xx+7CsNT3q8=; h=From:To:Cc:Subject:Date:Reply-To; b=I1W+4uqB0Ynd12gabPvEPf5uJynHVAzw2NpY7g5o7KSJ/I3PeloGrXAUPNdilGJr7 PkuihrGk1/P/eNzYv5D7R7aDt0MBnFmZeA1cyQYHNaEprw/nkXnx6I/N76mc/TK1G2 sgPtoXcb1ta8rfa71CXQa0QD0mqOnF8mLLr29Wq0= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-98994: statmount: read the parent of an unmounted mount under mount_lock Date: Fri, 23 Oct 2026 14:19:56 +0200 Message-ID: <2026102316-CVE-2026-98994-69fa@gregkh> X-Mailer: git-send-email 2.56.0 Reply-To: , X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2792; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=L0KfnJ0zIAhVw7gsED7ZPb9tW4sBx1TuaVkcvC1bZVI=; b=owGbwMvMwCRo6H6F97bub03G02pJDFm3A46ci7xtLPFva6uyo9TzOjfJ8AOxUx7/mx65xi80f sXcI3n2HbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRl7kMc0VaM6su/mvcJRrO oxCit9r2v2pPMsOCjRqTFzNVdyTctVvW+4qv8JnPgd5NAA== 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: statmount: read the parent of an unmounted mount under mount_lock statmount_mnt_basic() reads the ids of the parent through m->mnt_parent with namespace_sem held for reading. That's fine for a mount that is in a namespace. Everything above it is pinned by that namespace. STATMOUNT_BY_FD also accepts a file descriptor on a mount that has been unmounted on purpose and that only the file descriptor keeps alive. If that mount stayed attached to its parent when it was unmounted the parent is unmounted as well and nothing pins it for the child. The final mntput() unmounts the children under mount_lock alone and frees the parent afterwards. Concurrently, statmount_mnt_basic() reads m->mnt_parent twice while that can happen and can easily dereference a mount that's already gone. Read the parent of an unmounted mount under mount_lock. The parent can't be put while it is held and both ids come from the same mount. A mounted mount's parent is pinned by the namespace and a mount can't leave its namespace while namespace_sem is held, so the common case takes no global lock. The Linux kernel CVE team has assigned CVE-2026-98994 to this issue. Affected and fixed versions =========================== Issue introduced in 7.0 with commit 0e5032237ee5530147fbdf33134297e1490d5ec3 and fixed in 7.2.11 with commit 98fc6c7b6ca676157d2c780bd0a537b2c10fe08f Issue introduced in 7.0 with commit 0e5032237ee5530147fbdf33134297e1490d5ec3 and fixed in 7.3 with commit bb46094057520304073130920c223451c2a694a7 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-2026-98994 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/namespace.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/98fc6c7b6ca676157d2c780bd0a537b2c10fe08f https://git.kernel.org/stable/c/bb46094057520304073130920c223451c2a694a7