Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-21612 is a high-severity Cross-site Scripting (CWE-79) vulnerability. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 41th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2025-21612 is a cross-site scripting (XSS) vulnerability (CWE-79, CWE-80) in the TabberNeue MediaWiki extension, which enables tab creation on wikis. In versions prior to 2.7.2, the TabberTransclude.php file fails to properly escape user-supplied page names during output, allowing an XSS payload embedded in the page name to execute. The vulnerability carries a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L), indicating high severity due to its network accessibility and potential for significant confidentiality impact.
Unauthenticated attackers (PR:N) can exploit this vulnerability remotely over the network (AV:N) with low complexity and no user interaction required (UI:N). By supplying a malicious page name containing an XSS payload, attackers can inject and execute arbitrary JavaScript in the context of users viewing affected wiki pages, potentially leading to high confidentiality impact such as session hijacking or data theft, alongside low integrity and availability effects.
The vulnerability is addressed in TabberNeue version 2.7.2, where escaping was added to prevent payload execution. Relevant GitHub commits (d8c3db4e5935476e496d979fb01f775d3d3282e6 and f229cab099c69006e25d4bad3579954e481dc566) detail the fix, and the security advisory (GHSA-4x6x-8rm8-c37j) provides further guidance on updating the extension.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-0009
Vulnerability Data
TabberNeue is a MediaWiki extension that allows the wiki to create tabs. Prior to 2.7.2, TabberTransclude.php doesn't escape the user-supplied page name when outputting, so an XSS payload as the page name can be used here. This vulnerability is fixed…
more
in 2.7.2.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
—
V1.1.2V1.3.2V1.2.1V1.3.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.
Input validation directly enforces neutralization of untrusted data before it reaches web output generation.
Output filtering can catch or sanitize unneutralized script content before it is served to users.
Secure engineering principles include mandatory output encoding and neutralization of HTML metacharacters to stop injection at the source.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.
Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.
Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.
Requiring language-specific secure-coding standards and automated scanning during the SDLC catches missing output encoding or improper neutralization of untrusted data before the software reaches production.
Application security requirements explicitly call for neutralization of script-related HTML tags.
Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.