CVE-2026-33721

HIGH EPSS 54.1%
Published Mar 27, 20263mo ago · Modified Jun 17, 20261w ago
7.5 CVSS 3.1
High
Find Similar
Published Mar 27, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
54.1% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

CWE-787 Out-of-bounds Write Memory Safety

Affected Products 1

VendorProductVersionRange
osgeomapserver*≥4.2.0  –  <8.6.1

References 3

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

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.