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Vulnerability · Published Sep 23, 2020 · Assigned by mitre

CVE-2020-25601

Medium 5.5

In plain English

A medium-severity security flaw in the xen package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.4%top 63.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

An issue was discovered in Xen through 4.14.x. There is a lack of preemption in evtchn_reset() / evtchn_destroy(). In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these (when resetting all event channels or when cleaning up after the guest) may take extended periods of time. So far, there was no arrangement for preemption at suitable intervals, allowing a CPU to spend an almost unbounded amount of time in the processing of these operations. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. All Xen versions are vulnerable in principle. Whether versions 4.3 and older are vulnerable depends on underlying hardware characteristics.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20xen4.14.0-r1ALPINE-CVE-2020-25601
Alpine:v3.21xen4.14.0-r1ALPINE-CVE-2020-25601
Alpine:v3.22xen4.14.0-r1ALPINE-CVE-2020-25601
Alpine:v3.23xen4.14.0-r1ALPINE-CVE-2020-25601
Alpine:v3.24xen4.14.0-r1ALPINE-CVE-2020-25601
Debian:12xen4.14.0+80-gd101b417b7-1DEBIAN-CVE-2020-25601
Debian:13xen4.14.0+80-gd101b417b7-1DEBIAN-CVE-2020-25601
Debian:14xen4.14.0+80-gd101b417b7-1DEBIAN-CVE-2020-25601

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

References