VDB-240034 · CVE-2023-34322 · XSA-438

Xen on x86 Top-level Shadow Reference dropped privileges

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.7	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Xen on x86 and classified as critical. This vulnerability affects unknown code of the component Top-level Shadow Reference Handler. Executing a manipulation can lead to an unknown weakness. The identification of this vulnerability is CVE-2023-34322. There is no exploit available. A patch should be applied to remediate this issue.

Detailsinfo

A vulnerability has been found in Xen on x86 (Virtualization Software) (the affected version is unknown) and classified as critical. This vulnerability affects an unknown code of the component Top-level Shadow Reference Handler. The CWE definition for the vulnerability is CWE-273. The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. Since Xen itself needs to be mapped when PV guests run, Xen and shadowed PV guests run directly the respective shadow page tables. For 64-bit PV guests this means running on the shadow of the guest root page table. In the course of dealing with shortage of memory in the shadow pool associated with a domain, shadows of page tables may be torn down. This tearing down may include the shadow root page table that the CPU in question is presently running on. While a precaution exists to supposedly prevent the tearing down of the underlying live page table, the time window covered by that precaution isn't large enough.

The weakness was shared 09/20/2023 as XSA-438. The advisory is available at xenbits.xen.org. This vulnerability was named CVE-2023-34322 since 06/01/2023. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/16/2025). This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at xenbits.xen.org.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Virtualization Software

Name

License

open-source

CPE 2.3info

🔍

CPE 2.2info

🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Dropped privileges
CWE: CWE-273 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: xenbits.xen.org

Timelineinfo

06/01/2023 🔍
09/20/2023 +111 days 🔍
09/20/2023 +0 days 🔍
06/16/2025 +635 days 🔍

Sourcesinfo

Advisory: XSA-438
Status: Confirmed

CVE: CVE-2023-34322 (🔍)
GCVE (CVE): GCVE-0-2023-34322
GCVE (VulDB): GCVE-100-240034

Entryinfo

Created: 09/20/2023 14:31
Updated: 06/16/2025 22:40
Changes: 09/20/2023 14:31 (39), 06/16/2025 22:40 (29)
Complete: 🔍
Cache ID: 216::103