CVE-2026-52854

HIGHPre-NVD 8.68.6
EchelonGraph scoreLOW confidence

This high-severity CVE scores 8.6 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m
8.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: —CVSS: 8.6Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

mediawiki/maps has stored XSS through the overlays parameter in the display_map parser function

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.}}

Impact

Stored XSS can be performed by any user with the edit permission.

CVSS v3
8.6
EG Score
8.6(low)
EG Risk
43(Track)
EG Risk 43/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity86% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
—
KEV
Not listed

Published

July 2, 2026

Last Modified

July 2, 2026

Vendor Advisories for CVE-2026-52854(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
mediawiki/maps10.0.0 ... 9.0.7 (114 versions)12.1.3—

Data Freshness Timeline

(refreshed 1× in last 7d / 2× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 03:19 UTCEG score recompute
  2. 2026-07-02 18:06 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-52854?
CVE-2026-52854 is a high vulnerability published on July 2, 2026. mediawiki/maps has stored XSS through the overlays parameter in the display_map parser function 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…
When was CVE-2026-52854 disclosed?
CVE-2026-52854 was first published in the National Vulnerability Database on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-52854?
CVE-2026-52854 has a CVSS v4.0 base score of 8.6 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-52854?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-52854, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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