Vulnerability in Xen
CVE-2020-25604
An issue was discovered in Xen through 4.14.x. There is a race condition when migrating timers between x86 HVM vCPUs. When migrating timers of x86 HVM guests between its vCPUs, the locking model used allows for a second vCPU of the same guest (also operating on the timers) to release a lock that it didn't acquire. The most likely effect of the issue is a hang or crash of the hypervisor, i.e., a Denial of Service (DoS). All versions of Xen are affected. Only x86 systems are vulnerable. Arm systems are not vulnerable. Only x86 HVM guests can leverage the vulnerability. x86 PV and PVH cannot leverage the vulnerability. Only guests with more than one vCPU can exploit the vulnerability.
Vulnerability class: Race Condition
EPSS: 0.003 (17.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Xen
- Debian Debian_linux — versions 10.0
- Fedoraproject Fedora — versions 31, 32, 33
- Opensuse Leap — versions 15.2
- N/a — versions n/a
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve@mitre.org (Patch, x_refsource_MISC, Vendor Advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_SUSE)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)
Frequently asked questions
- What is CVE-2020-25604?
- CVE-2020-25604 is a medium-severity vulnerability in Xen, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 4.7/10. Published 2020-09-23.
- How severe is CVE-2020-25604?
- Medium severity. CVSS v3 base score is 4.7 out of 10.
- Is CVE-2020-25604 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.