CVE-2026-33721

7.5 highEPSS 1.2%

High (7.5) in osgeo mapserver. EPSS 1.2% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 1.2% chance of exploitation in the next 30 days; higher than 68% of CVEs (scores of 2026-10-31)
CWE: CWE-787
Published: 2026-03-27
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

osgeo:mapserver

References

https://github.com/MapServer/MapServer/releases/tag/rel-8-6-1
https://github.com/MapServer/MapServer/security/advisories/GHSA-cv4m-mr84-fgjp
https://lists.debian.org/debian-lts-announce/2026/04/msg00017.html

Check your stack JSON