{"cve":"CVE-2020-8834","nvd":{"published":"2020-04-09T22:15:12.050","modified":"2026-06-17T03:27:01.807","status":"Modified","description":"KVM in the Linux kernel on Power8 processors has a conflicting use of HSTATE_HOST_R1 to store r1 state in kvmppc_hv_entry plus in kvmppc_{save,restore}_tm, leading to a stack corruption. Because of this, an attacker with the ability run code in kernel space of a guest VM can cause the host kernel to panic. There were two commits that, according to the reporter, introduced the vulnerability: f024ee098476 (\"KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures\") 87a11bb6a7f7 (\"KVM: PPC: Book3S HV: Work around XER[SO] bug in fake suspend mode\") The former landed in 4.8, the latter in 4.17. This was fixed without realizing the impact in 4.18 with the following three commits, though it's believed the first is the only strictly necessary commit: 6f597c6b63b6 (\"KVM: PPC: Book3S PR: Add guest MSR parameter for kvmppc_save_tm()/kvmppc_restore_tm()\") 7b0e827c6970 (\"KVM: PPC: Book3S HV: Factor fake-suspend handling out of kvmppc_save/restore_tm\") 009c872a8bc4 (\"KVM: PPC: Book3S PR: Move kvmppc_save_tm/kvmppc_restore_tm to separate file\")","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H","score":6.5},"cwes":["CWE-362","CWE-368"],"references":["http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00035.html","https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1867717","https://usn.ubuntu.com/4318-1/","https://usn.ubuntu.com/usn/usn-4318-1","https://www.openwall.com/lists/oss-security/2020/04/06/2"],"products":["canonical:ubuntu_linux","linux:linux_kernel","opensuse:leap"],"source":"nvd","synced_at":"2026-10-19T21:03:08.679916934+00:00"},"epss":{"cve":"CVE-2020-8834","score":0.00347,"percentile":0.28347,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}