CVE-2026-42030

MapServer: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) in OpenLayers viewer

MEDIUM
6.1
CVSS Score
Published: May 8, 2026 at 03:56 PM UTC
Updated: June 17, 2026 at 10:47 AM UTC
2 products affected across 2 vendorsMapserverMapServer

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

MapServer is a system for developing web-based GIS applications. From version 6.0 to before version 8.6.2, a reflected XSS vulnerability in MapServer's WMS server allows an unauthenticated attacker to inject arbitrary HTML/JavaScript into the browser of any user who opens a crafted WMS URL. The vulnerability is triggered via FORMAT=application/openlayers combined with an unsanitized SRS parameter in WMS 1.3.0 requests. This issue has been patched in version 8.6.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.0.0 ≤ v < 8.6.2
v < 8.6.2
Affected range stops below 8.6.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/MapServer/MapServer/security/advisories/GHSA-4g9f-ph64-hg2x
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/MapServer/MapServer/releases/tag/rel-8-6-2

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-80

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