Description

MapServer is a system for developing web-based GIS applications. Starting in version 4.2 and prior to version 8.6.1, a heap-buffer-overflow write in MapServer’s SLD (Styled Layer Descriptor) parser lets a remote, unauthenticated attacker crash the MapServer process by sending a crafted SLD with more than 100 Threshold elements inside a ColorMap/Categorize structure (commonly reachable via WMS GetMap with SLD_BODY). Version 8.6.1 patches the issue.

INFO

Published Date :

2026-03-27T00:15:00.360Z

Last Modified :

2026-04-17T17:18:03.353Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-33721 vulnerability.

Vendors Products
Mapserver
  • Mapserver
Osgeo
  • Mapserver
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33721.

URL Resource
https://github.com/MapServer/MapServer/releases/tag/rel-8-6-1 cve-icon cve-icon cve-icon
https://github.com/MapServer/MapServer/security/advisories/GHSA-cv4m-mr84-fgjp cve-icon cve-icon cve-icon
https://lists.debian.org/debian-lts-announce/2026/04/msg00017.html cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-33721 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-33721 cve-icon
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CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact