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TI-2026-39247 Aliases CVE-2026-54355

MapServer: Reflected XSS in OpenLayers HTML Output via `HTTP_X_FORWARDED_HOST`

Priority MEDIUM 57CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
Impact type
Cross-site scripting
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

MapServer is a system for developing web-based GIS applications. From 6.0 until 8.6.4, MapServer's OpenLayers HTML output for SERVICE=WMS&REQUEST=GetMap&FORMAT=application/openlayers reflects an attacker-controlled X-Forwarded-Host value received as HTTP_X_FORWARDED_HOST through msBuildOnlineResource(), processLine(), and the [mapserv_onlineresource] substitution in src/maputil.c and src/maptemplate.c without escaping it for a single-quoted JavaScript string. When the deployment trusts the forwarded header and does not configure a fixed ows_onlineresource or MS_ONLINERESOURCE value, embedded single quotes can escape the generated URL string. An unauthenticated attacker can craft a URL that executes arbitrary JavaScript in the MapServer site origin when opened by a victim, enabling access to sessions or tokens, same-origin data and requests, and actions as the victim. This issue is fixed in version 8.6.4.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.005 43rd percentileScored 2026-11-07
Fix Fixed MapServer (MapServer): 8.6.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
OSGeoMapServer6.0 to before 8.6.48.6.4Patch availableCNA
  • MapServer VendorOSGeo Affected 6.0 to before 8.6.4 Fixed in 8.6.4 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:osgeo:mapserver:*:*:*:*:*:*:*:*——OSGeo
  • cpe:2.3:a:osgeo:mapserver:*:*:*:*:*:*:*:* Versions — — ·OSGeo

Remediation

  • Fix · CNA MapServer (MapServer) Fixed in 8.6.4

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-54355

References

Other 7

  • TI-2024-24187 Remote Code Execution (RCE) vulnerability in evaluating property name expressions in Geoserver KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-08629 Improper Control of Generation of Code in jai-ext KEVCVSS 3.1CRITICAL 10.0
  • TI-2025-36149 GeoServer is vulnerable to an Unauthenticated XML External Entities (XXE) attack via WMS GetMap feature KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-10619 Unfiltered SQL Injection Vulnerabilities in Geoserver CVSS 3.1CRITICAL 9.8
  • TI-2023-23486 WPS Server Side Request Forgery in GeoServer CVSS 3.1CRITICAL 9.8
  • TI-2025-36983 MapServer - WFS XML Filter Query SQL injection CVSS 4.0HIGH 8.9
See all 61 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences