Xen libfsimage iso9660 driver input validation

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 (≈)
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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.
5.5$0-$5k3.95-

Summaryinfo

A vulnerability categorized as critical has been discovered in Xen libfsimage. This issue affects some unknown processing of the component iso9660 driver. Executing a manipulation can lead to input validation. This vulnerability is registered as CVE-2026-42494. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as critical was found in Xen libfsimage (affected version unknown). This vulnerability affects an unknown functionality of the component iso9660 driver. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] The directory and Rock Ridge / SUSP walk in libfsimage's iso9660 driver derives several lengths directly from attacker-controlled on-disk fields without validating them: * The directory loop itself assumes a good record length. This is CVE-2026-42494. * The calculation of the System Use area may underflow. This is CVE-2026-42495. * The Rock Ridge extension loop assumes a good (inner) record length. This is CVE-2026-62423. * The Rock Ridge NM record processing assumes a good entry length. This is CVE-2026-62424. * The Rock Ridge CE record processing assumes a good size and offset. This is CVE-2026-62425.

The advisory is shared for download at xenbits.xenproject.org. This vulnerability was named CVE-2026-42494 since 04/27/2026. The exploitation appears to be easy. The attack can be initiated remotely. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/28/2026).

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

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.5
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/27/2026 CVE reserved
07/28/2026 +92 days Advisory disclosed
07/28/2026 +0 days VulDB entry created
07/28/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: xenbits.xenproject.org
Status: Confirmed

CVE: CVE-2026-42494 (🔒)
GCVE (CVE): GCVE-0-2026-42494
GCVE (VulDB): GCVE-100-383860

Entryinfo

Created: 07/28/2026 15:31
Changes: 07/28/2026 15:31 (52)
Complete: 🔍
Cache ID: 216::103

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