Citizen vulnerable to stored XSS in sticky header button messages

published 2025-10-17 12 mo ago modified 2026-10-08 31 d ago also EUVD-2025-34930 , GHSA-g955-vw6w-v6pp

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

Citizen is a MediaWiki skin that makes extensions part of the cohesive experience. Citizen from 3.3.0 to 3.9.0 are vulnerable to stored cross-site scripting in the sticky header button message handling. In stickyHeader.js the copyButtonAttributes function assigns innerHTML from a source element’s textContent when copying button labels. This causes escaped HTML in system message content (such as citizen-share, citizen-view-history, citizen-view-edit, and nstab-talk) to be interpreted as HTML in the sticky header, allowing injection of arbitrary script by a user with the ability to edit interface messages. The vulnerability allows a user with the editinterface right but without the editsitejs right (by default the sysop group has editinterface but may not have editsitejs) to execute arbitrary JavaScript in other users’ sessions, enabling unauthorized access to sensitive data or actions. The issue is fixed in 3.9.0.

Patch / fix

fixed in 2 links 2

packagist starcitizentools/citizen-skin 3.9.0
starcitizen.tools citizen 3.9.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 12 mo ago (2025-10-17)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
GitHub	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
packagist	starcitizentools/citizen-skin	>=3.3.0, <3.9.0	3.9.0

Affected products

StarCitizenTools mediawiki-skins-Citizen

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary