What is the CVSS score of CVE-2025-56537?

CVE-2025-56537 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

OpenNebula CVE-2025-56537

EUVD-2025-209591 MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-04-29 cve@mitre.org

XSS Opennebula

6.1

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

6.1 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

vuln.today AI

5.4 MEDIUM

PR:L assigned because writing virtual network templates in OpenNebula requires authenticated platform access, not unauthenticated submission; all other metrics match stored XSS with Changed scope.

3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

4.0 AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Jul 24, 2026 - 05:45 vuln.today

CVSS changed

Apr 29, 2026 - 17:22 NVD

6.1 (MEDIUM)

EUVD ID Assigned

Apr 29, 2026 - 16:22 euvd

EUVD-2025-209591

CVE Published

Apr 29, 2026 - 16:16 nvd

MEDIUM 6.1

DescriptionCVE.org

A stored cross-site scripting (XSS) vulnerability in opennebula v6.10.0.1 and fixed in v.7.0 allows attackers to execute arbitrary web scripts or HTML via injecting a crafted payload into the virtual network template parameter.

AnalysisAI

Stored cross-site scripting in OpenNebula v6.10.0.1 allows an attacker to persist a malicious payload inside the virtual network template parameter, which then executes in the browser of any user who views the affected template. The Changed scope (S:C) in the CVSS vector confirms the injected script runs in the victim's browsing context, enabling session theft, credential harvesting, or UI redressing against platform administrators. A public proof-of-concept is confirmed by SSVC data; exploitation is not confirmed in CISA KEV, and the EPSS score of 0.03% (8th percentile) indicates low observed exploitation activity despite the POC's existence.

Technical ContextAI

OpenNebula is an open-source cloud infrastructure management platform used to orchestrate virtual machines and networks. The vulnerability resides in the web frontend's handling of virtual network template parameters, which fails to properly neutralize user-supplied input before storing and later rendering it in a web page - a textbook CWE-79 (Improper Neutralization of Input During Web Page Generation) defect. The injected payload is persisted server-side and delivered to any subsequent viewer's browser, distinguishing this as stored (persistent) XSS rather than reflected or DOM-based. Affected product is identified by CPE cpe:2.3:a:opennebula:opennebula:*:*:*:*:*:*:*:* covering the v6.10.0.1 release line. The Changed scope metric in the CVSS vector indicates that the JavaScript executes outside the origin of the vulnerable parameter input, affecting the broader authenticated session.

RemediationAI

The primary remediation is upgrading to OpenNebula v7.0, which contains the vendor-released fix as confirmed by the official release page at https://opennebula.io/opennebula-7/. Until upgrade is possible, compensating controls should focus on restricting who can create or modify virtual network templates: limit template write permissions to fully trusted administrators only, removing that capability from lower-privileged or semi-trusted user roles. Additionally, deploying a Content Security Policy (CSP) header on the OpenNebula Sunstone web interface that blocks inline script execution can reduce the impact of any stored payloads, though CSP configuration has its own complexity trade-offs and may break legitimate UI functionality if not tested carefully. Input validation at the application layer (WAF rules blocking common XSS patterns in template parameter fields) can also reduce exposure but should not be treated as a complete substitute for patching.