{"id":"CVE-2026-89920","published":"2026-09-16T11:17:01.073","lastModified":"2026-09-16T15:18:18.237","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: Fix memory corruption by not reinjecting CK machine checks\n\nChannel-subsystem damage machine checks are for the host channel\nsubsystem. The guest channel subsystem is emulated in the userspace VMM.\nThere is no point in forwarding such machine checks into the guest.\n\nThis also simplifies the machine check reinjection and avoids kfree of a\nstack variable as reported by sashiko.  There might be still machine\nchecks that have the ck bit set with another bit (like instruction\ndamage), mask out the CK bit in s390_backup_mcck_info(), like the CP and\nED bits already are.","cvssScore":7.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/546dde823a36d7283dcf46127c2f3d093443860f","tags":[]},{"url":"https://git.kernel.org/stable/c/6ee52d3af2a1bf70349cf3f860933c8d221e229a","tags":[]},{"url":"https://git.kernel.org/stable/c/7077ec953996acc04b49d1dfc43df1c1a2a74395","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"This vulnerability in the Linux kernel's KVM s390 implementation allows for potential memory corruption by improperly handling machine checks related to the channel subsystem. It matters because it could lead to arbitrary code execution if exploited.","exploitability":"Exploitation is considered difficult as it requires specific conditions and knowledge of the affected kernel version. Precondition is the presence of a vulnerable KVM s390 environment.","blast_radius":"If exploited, the impact could be severe, potentially leading to full system compromise and arbitrary code execution on the host system.","remediation":"Upgrade to the fixed version 5.10.147 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["kernel","s390","memory-corruption","vulnerability"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-10-08T08:43:04.777Z"}}