CVE-2025-42620
Published: 08 December 2025
Summary
CVE-2025-42620 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Circl (inferred from references). Its CVSS base score is 8.3 (High).
Operationally, ranked at the 16.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-201710
- 🇱🇺 CIRCL: vulnerability.circl.lu
Vulnerability details
In affected versions, vulnerability-lookup handled user-controlled content in comments and bundles in an unsafe way, which could lead to stored Cross-Site Scripting (XSS). On the backend, the related_vulnerabilities field of bundles accepted arbitrary strings without format validation or proper sanitization.…
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On the frontend, comment and bundle descriptions were converted from Markdown to HTML and then injected directly into the DOM using string templates and innerHTML. This combination allowed an attacker who could create or edit comments or bundles to store crafted HTML/JavaScript payloads which would later be rendered and executed in the browser of any user visiting the affected profile page (user.html). This issue affects Vulnerability-Lookup: before 2.18.0.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.
Validates web inputs to reject script-related content that could produce XSS.
Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.