CVE-2026-33721

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/MapServer/MapServer/releases/tag/rel-8-6-1	Product Release Notes
https://github.com/MapServer/MapServer/security/advisories/GHSA-cv4m-mr84-fgjp	Exploit Mitigation Vendor Advisory
https://lists.debian.org/debian-lts-announce/2026/04/msg00017.html

Configurations

Configuration 1 (hide)

cpe:2.3:a:osgeo:mapserver:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-03-27 01:16

Updated : 2026-06-17 10:37

NVD link : CVE-2026-33721

Mitre link : CVE-2026-33721

CVE.ORG link : CVE-2026-33721

JSON object : View

Products Affected

osgeo

mapserver

CWE

CWE-787

Out-of-bounds Write

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