VDB-377217 · CVE-2026-23556 · GCVE-0-2026-23556

Xen oxenstored Usage Counts missing release of file descriptor or handle after effective lifetime

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.
2.7	$0-$5k	0.56

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Xen oxenstored. Impacted is an unknown function of the component Usage Counts. Performing a manipulation results in missing release of file descriptor or handle after effective lifetime. This vulnerability is reported as CVE-2026-23556. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic has been found in Xen oxenstored (affected version unknown). This affects an unknown functionality of the component Usage Counts. The manipulation with an unknown input leads to a missing release of file descriptor or handle after effective lifetime vulnerability. CWE is classifying the issue as CWE-775. The product does not release a file descriptor or handle after its effective lifetime has ended, i.e., after the file descriptor/handle is no longer needed. This is going to have an impact on integrity. The summary by CVE is:

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked. When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

The advisory is shared at xenbits.xen.org. This vulnerability is uniquely identified as CVE-2026-23556 since 01/14/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Additional levels of successful authentication are required for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/09/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Virtualization Software

Vendor

Name

oxenstored

License

open-source

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 2.7
VulDB Meta Temp Score: 2.7

VulDB Base Score: 2.7
VulDB Temp Score: 2.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Missing release of file descriptor or handle after effective lifetime
CWE: CWE-775 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

01/14/2026 CVE reserved
07/09/2026 +175 days Advisory disclosed
07/09/2026 +0 days VulDB entry created
07/09/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: xenbits.xen.org
Status: Confirmed

CVE: CVE-2026-23556 (🔒)
GCVE (CVE): GCVE-0-2026-23556
GCVE (VulDB): GCVE-100-377217

Entryinfo

Created: 07/09/2026 17:53
Changes: 07/09/2026 17:53 (52)
Complete: 🔍
Cache ID: 216::103