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 47CAF4FC8C9 for ; Fri, 4 Sep 2026 17:15:22 +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=1788542123; cv=none; b=PDwp9nC6pysvBTPnI8ZUSSNdocZRzUpyugOkl0BLzWeosyxPH1JPxcKsbzEaqXqi39pBUtnlG3GOkNkQHGnLju320YXd/YDtvasuDhp2iNy/RMNGVohqx+krT9laUb2yK4fDZ5Q0DwkqSlzAeEfCVtganQMsOTEzsKwvyNxY+gY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788542123; c=relaxed/simple; bh=Q0q4NAWDU2s5vtx8dIU+6BXLYRHYRk9gorwJt7uQNhg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ERxnulRLtJYAzM4ZJsF3WZPIR4jokRWQ/qawi4g3Hm/2eCQqX6/s668QzytB0ts1ZK1GINALo107979CWNvGTAVEDrviXeE+asZwBtI3hZcDuQOav1JD52iXWDuqxQnzeDkkkKGrttEoIJ4ZtOL9ljeycz+m8Rpn27HcUbufeGU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Z9f6Adrc; 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="Z9f6Adrc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B88A91F00A3D; Fri, 4 Sep 2026 17:15:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788542121; bh=Q7WtNCQy3QI+UAsMWqPFPdCA39xNqLCDg00W8P5H+6E=; h=From:To:Cc:Subject:Date:Reply-To; b=Z9f6Adrc3rkDUMcgNDUduYyN56FgTYn8RAE7K3cJa8LHf4H5neIfxXC/mFvXPFmPU EZkikJ41Wz89Pqmh0467lNxAYbbORfUS0d29cD5oDd5s70/Z7SPN1yRKD5GEhddBK4 NEW0JQycCV7tZTxxRcE1lrPddZ9soaq03teDlwGk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80896: mshv: Fix race in mshv_irqfd_deassign Date: Fri, 4 Sep 2026 19:09:37 +0200 Message-ID: <2026090430-CVE-2026-80896-97e0@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=2926; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=z9kpDJxavOAudbiLrYVSnjIIPsHOYArAv8MfJlbwGgk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmzfnsJVsbfu79hqteum+5n9umEqZ4O97Ja9XK/rdJiJ XP7r66cHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjARezuG+en3X//qMBErY7h8 w/P39zcf6o03FDAsWPQ+6krWl8iTsmvzLmfIKfYt8V7DDgA= 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: mshv: Fix race in mshv_irqfd_deassign mshv_irqfd_deactivate() and the hlist traversal of pt_irqfds_list require pt->pt_irqfds_lock to be held, but mshv_irqfd_deassign() omits it. This races with the EPOLLHUP path in mshv_irqfd_wakeup(), which does take the lock before calling mshv_irqfd_deactivate(). Additionally, mshv_irqfd_deactivate() uses hlist_del() which poisons the node pointers rather than resetting them. Since mshv_irqfd_is_active() relies on hlist_unhashed() (checks pprev == NULL), a poisoned node still appears active. If a concurrent path calls mshv_irqfd_deactivate() again on the same irqfd, the guard fails to prevent a double hlist_del() on poisoned pointers. Fix both issues: - Add the missing spin_lock_irq/spin_unlock_irq around the list traversal in mshv_irqfd_deassign(), matching mshv_irqfd_release(). - Use hlist_del_init() instead of hlist_del() so the node is properly marked as unhashed after removal, making the is_active guard reliable. The Linux kernel CVE team has assigned CVE-2026-80896 to this issue. Affected and fixed versions =========================== Issue introduced in 6.15 with commit 621191d709b14882270dfd8ea5d7d6cdfebe2c35 and fixed in 6.18.44 with commit 72a90ce4918b5a2d4820fe20677ba9af780d8826 Issue introduced in 6.15 with commit 621191d709b14882270dfd8ea5d7d6cdfebe2c35 and fixed in 7.1.8 with commit 4529a41a675b96e0f876eef1cc93a31a57cb4d18 Issue introduced in 6.15 with commit 621191d709b14882270dfd8ea5d7d6cdfebe2c35 and fixed in 7.2 with commit 0762262ac3e70f65b3bb843fe892f8bac1562d08 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-2026-80896 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: drivers/hv/mshv_eventfd.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/72a90ce4918b5a2d4820fe20677ba9af780d8826 https://git.kernel.org/stable/c/4529a41a675b96e0f876eef1cc93a31a57cb4d18 https://git.kernel.org/stable/c/0762262ac3e70f65b3bb843fe892f8bac1562d08