CVE-2024-45818

Dec. 31, 2024, 7:15 p.m.

6.5
Medium

Description

The hypervisor contains code to accelerate VGA memory accesses for HVM guests, when the (virtual) VGA is in "standard" mode. Locking involved there has an unusual discipline, leaving a lock acquired past the return from the function that acquired it. This behavior results in a problem when emulating an instruction with two memory accesses, both of which touch VGA memory (plus some further constraints which aren't relevant here). When emulating the 2nd access, the lock that is already being held would be attempted to be re-acquired, resulting in a deadlock. This deadlock was already found when the code was first introduced, but was analysed incorrectly and the fix was incomplete. Analysis in light of the new finding cannot find a way to make the existing locking discipline work. In staging, this logic has all been removed because it was discovered to be accidentally disabled since Xen 4.7. Therefore, we are fixing the locking problem by backporting the removal of most of the feature. Note that even with the feature disabled, the lock would still be acquired for any accesses to the VGA MMIO region.

Product(s) Impacted

Product Versions
Xen Hypervisor

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-667
Improper Locking
The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

References

https://xenbits.xenproject.org/xsa/advisory-463.html
http://www.openwall.com/lists/oss-security/2024/11/12/2
http://xenbits.xen.org/xsa/advisory-463.html

Tags

security@xen.org
CWE-667
2024-12-19
CVE-2024-45818

CVSS Score

6.5 / 10

CVSS Data - 3.1

  • Attack Vector: LOCAL
  • Attack Complexity: LOW
  • Privileges Required: LOW
  • Scope: CHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: NONE
  • Availability Impact: NONE

    • CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

    View Vector String

Timeline

Published: Dec. 19, 2024, 12:15 p.m.
Last Modified: Dec. 31, 2024, 7:15 p.m.

Status : Awaiting Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

security@xen.org

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.