VDB-372216 · CVE-2026-42490 · Nessus 321439

Xen permission

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.
6.3	$5k-$25k	5.40-

Summaryinfo

A vulnerability described as critical has been identified in Xen. This impacts an unknown function. The manipulation results in permission. This vulnerability is identified as CVE-2026-42490. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in Xen (unknown version). Affected is an unknown code block. The manipulation with an unknown input leads to a permission vulnerability. CWE is classifying the issue as CWE-275. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To create and manage guests, domctl operations are used by the control domain, a possible Xenstore domain, or by a domain controlling a particular guest. Some of these operations may not be executed in parallel, so a system-wide lock is used. The way that lock is acquired is, however, not providing any fairness. This is CVE-2026-42489. Furthermore, with XSM/Flask in use, the lock acquire will, for some operations, occur ahead of any permission checking. This is CVE-2026-42490.

The weakness was released by Andrew Cooper. The advisory is shared for download at xenbits.xenproject.org. This vulnerability is traded as CVE-2026-42490 since 04/27/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 06/19/2026). The MITRE ATT&CK project declares the attack technique as T1222.

The vulnerability scanner Nessus provides a plugin with the ID 321439 (Fedora 44 : xen (2026-24b84f97af)), which helps to determine the existence of the flaw in a target environment.

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

The vulnerability is also documented in the vulnerability database at Tenable (321439). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Virtualization Software

Name

License

open-source

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.3

VulDB Base Score: 6.3
VulDB Temp Score: 6.3
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: Permission
CWE: CWE-275 / CWE-266
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

Nessus ID: 321439
Nessus Name: Fedora 44 : xen (2026-24b84f97af)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/27/2026 CVE reserved
06/18/2026 +52 days Advisory disclosed
06/18/2026 +0 days VulDB entry created
06/19/2026 +1 days VulDB entry last update

Sourcesinfo

Advisory: xenbits.xenproject.org
Researcher: Andrew Cooper
Status: Confirmed

CVE: CVE-2026-42490 (🔒)
GCVE (CVE): GCVE-0-2026-42490
GCVE (VulDB): GCVE-100-372216

Entryinfo

Created: 06/18/2026 17:29
Updated: 06/19/2026 05:42
Changes: 06/18/2026 17:29 (52), 06/19/2026 05:42 (2)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.