Uncontrolled Recursion Affecting xen-libs package, versions <4.10.4_24-3.53.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (21st percentile)

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  • Snyk IDSNYK-SLES150-XENLIBS-2692190
  • published14 Apr 2022
  • disclosed22 Dec 2020

Introduced: 22 Dec 2020

CVE-2020-29566  (opens in a new tab)
CWE-674  (opens in a new tab)

How to fix?

Upgrade SLES:15.0 xen-libs to version 4.10.4_24-3.53.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen-libs package and not the xen-libs package as distributed by SLES. See How to fix? for SLES:15.0 relevant fixed versions and status.

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.

CVSS Scores

version 3.1