Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Authenticator XSS is network-reachable with no authentication required; scope change reflects browser-context execution; no availability impact and limited confidentiality and integrity effects.
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
A cross-site scripting (XSS) vulnerability in the custom authenticator driver of opennebula v6.10.0.1 allows attackers to execute arbitrary web scripts or HTML via a crafted payload.
AnalysisAI
Cross-site scripting in OpenNebula v6.10.0.1's custom authenticator driver enables unauthenticated remote attackers to inject arbitrary JavaScript or HTML into victims' browsers via a crafted payload delivered through the authentication interface. A public proof-of-concept exploit exists (SSVC exploitation: poc, GitHub PoC referenced), though EPSS at 0.03% indicates minimal current exploitation activity and CISA KEV listing is absent. Because the vulnerable component is the authenticator driver - the portal login surface - successful exploitation could facilitate session token theft or credential phishing targeting cloud administrators, making impact disproportionate to the Medium CVSS score in privileged-user scenarios.
Technical ContextAI
OpenNebula is an open-source cloud computing management platform used to provision and orchestrate virtualized data center infrastructure. The vulnerability resides in the custom authenticator driver - the subsystem responsible for handling authentication requests and rendering the login interface in the Sunstone web portal. CWE-79 (Improper Neutralization of Input During Web Page Generation) identifies the root cause as insufficient sanitization or output encoding of attacker-controlled input before it is reflected or stored within the HTML response, allowing script injection. The CPE string cpe:2.3:a:opennebula:opennebula:*:*:*:*:*:*:*:* uses a version wildcard, indicating NVD has not formally bounded the affected release range beyond the explicitly named 6.10.0.1. The CVSS scope change (S:C) is consistent with XSS executing in the victim browser's security context, distinct from the server-side application context.
RemediationAI
Upgrade to OpenNebula 7, as the reference to https://opennebula.io/opennebula-7/ in the vulnerability disclosure implies version 7 addresses this issue; however, a specific patched release number and corresponding vendor advisory have not been independently confirmed from available data - verify against official OpenNebula release notes before deploying. As a compensating control, restrict access to the Sunstone web portal (typically exposed on port 9869 or via reverse proxy on 80/443) to trusted internal networks or VPN-connected clients, reducing the population of potential victims who can receive crafted payloads. If the OpenNebula deployment supports configuring HTTP response headers, adding a restrictive Content-Security-Policy header can reduce the impact of injected scripts by limiting permitted script sources; note this is a mitigation, not a fix, and header support depends on the reverse proxy or web server in front of Sunstone. Restricting network access does not remediate the vulnerability and does not protect against internal threat actors. The VulDB advisory at https://vuldb.com/vuln/360181 and the PoC repository at https://github.com/MarkArtamonov/OpenNebula-CVE-2025-56534 should be monitored for updated patch information.
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-209587