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 90FBE4EE87F for ; Wed, 16 Sep 2026 10:39:13 +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=1789555167; cv=none; b=Jv+AGkhev2ZDucVPvLO6onfBsPq6Z64sDCqQOPHf3xaR0RlzWO+fXpkCsZN5DnhWjuYjqknMjdGrCQwpmpyeXedzuuYdl0PWQKxp5ivaJzFYDO4JF4zbKzDUquMuJLIl57bW6a1UiKN+z2+al4eYlcByIigPT3+hnLTiN+OXD5A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789555167; c=relaxed/simple; bh=Fx5r0QJxLXHsUdUlsHjbr9H+LWIflq5/JKOiPmR2358=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=rjiXgsE2ETn0a+Wd6HFiTkr5HMEdgfFgRsnxDJ00lPmdLf/4KQe/WUJISLi7M1Wl9p/5yRUQ1n39m1XcO1mLBYoVr3O3P4Q6/DXDd2N+ezj0QAfF4C9YAhTP0uiy7tGBBZ04gsSaczxKaKAc4rqFB3JFS8jahQ50KpAx1leoNXU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MzAqh4AW; 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="MzAqh4AW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 597781F0089B; Wed, 16 Sep 2026 10:39:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789555147; bh=XsmsDqOVDWSBWTEoDJNjNLQ9OhryvR2ZEUFHb9x3qHg=; h=From:To:Cc:Subject:Date:Reply-To; b=MzAqh4AWrZJy+6jj7y+hRUpoLDTCBQOikV6wHKNxZ/vNVIGm4T4VX434lFtUUT4xg QBKxjoVZYiOSFxvlSuUsZpk+wSte2UBt8TN3CBfDY95k0fy8JtwToJUAHbp8NWpN5Y A0OebQwBIbS4UK0aNOYnOqYxRstG7tbCqnPwxgXk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89920: KVM: s390: Fix memory corruption by not reinjecting CK machine checks Date: Wed, 16 Sep 2026 11:30:50 +0100 Message-ID: <2026091643-CVE-2026-89920-e6ab@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=2581; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=vYfLogUEyXycEu5f8dvkbK5i4HFChUcYiB5ORNVjytk=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmr8qdvmp8SXPnJJtxia5qLRYxcd+hKwdC3Gt++JubzH +9nXvesI5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACbCncowV1xUXm5yMu/GWwck lJ9I/w291bSnmmF+zJOnPLm3fm6UOpty9WGGXudLi+jbAA== 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: s390: Fix memory corruption by not reinjecting CK machine checks Channel-subsystem damage machine checks are for the host channel subsystem. The guest channel subsystem is emulated in the userspace VMM. There is no point in forwarding such machine checks into the guest. This also simplifies the machine check reinjection and avoids kfree of a stack variable as reported by sashiko. There might be still machine checks that have the ck bit set with another bit (like instruction damage), mask out the CK bit in s390_backup_mcck_info(), like the CP and ED bits already are. The Linux kernel CVE team has assigned CVE-2026-89920 to this issue. Affected and fixed versions =========================== Issue introduced in 4.13 with commit 4d62fcc0b692e3b4058d7d138114c27cd8b011f7 and fixed in 6.18.51 with commit 6ee52d3af2a1bf70349cf3f860933c8d221e229a Issue introduced in 4.13 with commit 4d62fcc0b692e3b4058d7d138114c27cd8b011f7 and fixed in 7.2.5 with commit 7077ec953996acc04b49d1dfc43df1c1a2a74395 Issue introduced in 4.13 with commit 4d62fcc0b692e3b4058d7d138114c27cd8b011f7 and fixed in 7.3-rc1 with commit 546dde823a36d7283dcf46127c2f3d093443860f 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-2026-89920 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/s390/include/asm/nmi.h arch/s390/kernel/nmi.c arch/s390/kvm/interrupt.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/6ee52d3af2a1bf70349cf3f860933c8d221e229a https://git.kernel.org/stable/c/7077ec953996acc04b49d1dfc43df1c1a2a74395 https://git.kernel.org/stable/c/546dde823a36d7283dcf46127c2f3d093443860f