CVEvulnerability

CVE-2020-29566

5.5 MEDIUM Published 2020-12-15 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2020-12-15
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
5.5 MEDIUM — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0 ([email protected])
4.9 MEDIUM — AV:L/AC:L/Au:N/C:N/I:N/A:C
Weaknesses
CWE-674

Description

An issue was discovered in Xen through 4.14.x. When they require assistance from the device model, x86 HVM guests must be temporarily de-scheduled. The device model will signal Xen when it has completed its operation, via an event channel, so that the relevant vCPU is rescheduled. If the device model were to signal Xen without having actually completed the operation, the de-schedule / re-schedule cycle would repeat. If, in addition, Xen is resignalled very quickly, the re-schedule may occur before the de-schedule was fully complete, triggering a shortcut. This potentially repeating process uses ordinary recursive function calls, and thus could result in a stack overflow. A malicious or buggy stubdomain serving a HVM guest can cause Xen to crash, resulting in a Denial of Service (DoS) to the entire host. Only x86 systems are affected. Arm systems are not affected. Only x86 stubdomains serving HVM guests can exploit the vulnerability.

Affected configurations

• xen xen (<= 4.14.0) • debian debian linux 10.0 • fedoraproject fedora 32 • fedoraproject fedora 33

Related

Weakness · CWE (1)

  • CWE-674 Uncontrolled Recursion weakness

References