🛡️ CVE-2026-42030 — mapserver

🟡 CVSS 6.1 — Medium ⚠️ Exploit Public CWE-80 NVD

6.1

CVSS Score

0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-42030 is classified as CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream…

Affected software

CVE-2026-42030 is recorded against 1 package.

mapserver (from 6.0.0 up to 8.6.2)

Timeline and source

Published on 8 May 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com
github.com
github.com

CVE-2026-42030 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Debian Ubuntu

Details

Severity MEDIUM

CVSS Score 6.1

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE CWE-80

Public Exploit ⚠️ Yes

Source NVD

Published 2026-05-08

Updated 2026-08-20

Modified 2026-06-17

Fix URL N/A

Affected Packages

Software	From version	Fixed in
mapserver	6.0.0	8.6.2

References

Product, Release Notes https://github.com/MapServer/MapServer/releases/tag/rel-8-6-2

Exploit, Vendor Advisory https://github.com/MapServer/MapServer/security/advisories/GHSA-4g9f-ph64-hg2x

🔗 NVD 🔗 Mitre

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Exploit Protection

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