highCVSS 8.6Vulnerability

CVE-2026-52854

### Summary Stored XSS through wikitext can be performed by inserting malicious HTML into the `overlays` parameter of the `display_map` parser function when using the leaflet service. ### Details The maps extension doesn't escape overlay names before passing them to leaflet. Leaflet then inserts them as HTML: https://github.com/ProfessionalWiki/Maps/blob/ca5139fabd75f3c34f47ea3fd161306506b053bc/resources/lib/leaflet/leaflet.js#L5243 ### PoC Preview the following wikitext, using the default configuration options of the extension: ``` {{#display_map:0,0|service=leaflet|overlays=OpenTopoMap.<img src=x onerror="alert(1);">}} ``` ### Impact Stored XSS can be performed by any user with the `edit` permission.

Properties

ghsa_id
GHSA-4h7g-5542-v3fc
summary
mediawiki/maps has stored XSS through the overlays parameter in the display_map parser function
severity
high
cvss_score
8.6
cve_id
CVE-2026-52854
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
is_ghsa_only
false
ghsa_published
2026-07-02T17:51:24Z
source_url
https://github.com/advisories/GHSA-4h7g-5542-v3fc
ghsa_updated
2026-07-02T17:51:27Z

Related Entities (5)

AFFECTS (1)

[Software]composer/mediawiki/maps

HAS_WEAKNESS (2)

[Weakness]Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
[Weakness]Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

REPORTED_BY (1)

[Source]GitHub Advisory Database

VULNERABLE_TO (1)

[Software]composer/mediawiki/maps

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CVE-2026-52854 (CVSS 8.6) — Ninja Signal Threat Intelligence | Ninja Signal