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 2C04333EAF9 for ; Sat, 22 Aug 2026 15:34:18 +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=1787412859; cv=none; b=ZLB5kbH0Ik670Ahxe+V5KHUi5fwGxPsEFnnO8iToJj4+4iDkhezv0SdMzAP/kZrndXYU6q+WLpWQy/nl62y1b+uQIMPVjBjIxdzBA6uGoMSjAKPZxjPr/thYr5OTN5hXYmPA3vMwwQ68RlrnpQsb5fnrELOgVDwi9sUKnBBJDRU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787412859; c=relaxed/simple; bh=InXgrZvkcyV60HHkBbjGQVb6OisBv07a5LzdPuFirEs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=cVHHuuylL6Z0Oe9gQBIBJS1HoMT30baaflEIxZXoH2olK8O/TlHNfK87Xwp88yKcn2s3lchB9n9MFUAeYHeiW4+qPobQaykhWoi0xfCDODolKFYkN2rJ4DguZ/OdUztWzxIe1X+Yy7k6CB2SSRpR9sCPBVl2zrFAgODHTwM0wc8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ls9juLdJ; 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="Ls9juLdJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33DBD1F000E9; Sat, 22 Aug 2026 15:34:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787412857; bh=zhH//MLPV7eFEMX+RLtEURiuu+UR98Xi+BIcPh2nYd8=; h=From:To:Cc:Subject:Date:Reply-To; b=Ls9juLdJ952pbRyRbgXz+mITiDLZMUJjz8NGhDlLM26DXOXBGp5SZK9tKBHQv9ID1 OHKZfpTJuppPnqbQF71NGYdrj/jylm15kxJCeHGvUMHJn7B7xA+mJFsJcLNXd2ud5k BpDjgkB4Bjh2zXlNEsNSh622vYh8EmszjkzwoH/0= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74607: KVM: SVM: Serialize accesses to the owner and mirror list with separate lock Date: Sat, 22 Aug 2026 17:31:31 +0200 Message-ID: <2026082216-CVE-2026-74607-533e@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=3257; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=EoKQApAP3qPTUgbfADyZ/znuLVPDdaTqUxnw5n8HszM=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmdB44IVF3wDHJwvydnd3BL0cWkzbXPztgJvnB3WD+TS fa9bcfLjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjIlV8Mc7gvVxfEW0WeDZGJ uz1vSYHtNBtbHoZ56j5Rs7clX1LwFzzurXrQb4XBisj3AA== 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: KVM: SVM: Serialize accesses to the owner and mirror list with separate lock Interaction between KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM and KVM_CAP_VM_COPY_ENC_CONTEXT_FROM can cause two separate issues: - in sev_migrate_from(), when the destination KVM is a mirror, the mirror entry is moved from the source's list to the owner's mirror_vms list, without holding the owner's lock unlike other writers of the owner's mirror list (sev_vm_copy_enc_context_from(), sev_vm_destroy()). A concurrent COPY or destroy can race with sev_migrate_from() and corrupt the list. - In sev_vm_destroy(), the *owner* is still active and could receive concurrently a KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM that causes sev->enc_context_owner to change. In this case the incorrect VM receives kvm_put_kvm(). The second issue needs particular care because the owner could disappear altogether (even though the race window is impossibly small) between reading it and locking it. There is thus no way to perform the checks under the owner lock without putting struct kvm under SLAB_TYPESAFE_BY_RCU (which would allow kvm_get_kvm_safe() under RCU critical section). It is much simpler to just use a global lock, since the critical sections are so small and the new lock is always a leaf lock. The Linux kernel CVE team has assigned CVE-2026-74607 to this issue. Affected and fixed versions =========================== Issue introduced in 5.18 with commit b2125513dfc0dd0ec5a9605138a3c356592cfb73 and fixed in 6.18.45 with commit 47976eaaf0a4eb46dade48b3246779090db9e3ec Issue introduced in 5.18 with commit b2125513dfc0dd0ec5a9605138a3c356592cfb73 and fixed in 7.1.9 with commit d728baba0f20e49439fc7831bf3e4e7dee82161a Issue introduced in 5.18 with commit b2125513dfc0dd0ec5a9605138a3c356592cfb73 and fixed in 7.2 with commit 1d78d33275ef2a16c6d080910b291d0a97a0e613 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-2026-74607 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: arch/x86/kvm/svm/sev.c arch/x86/kvm/svm/svm.h 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/47976eaaf0a4eb46dade48b3246779090db9e3ec https://git.kernel.org/stable/c/d728baba0f20e49439fc7831bf3e4e7dee82161a https://git.kernel.org/stable/c/1d78d33275ef2a16c6d080910b291d0a97a0e613