CVE-2026-33721

Severity CVSS v4.0:

Pending analysis

Type:

CWE-787 Out-of-bounds Write

Publication date:

27/03/2026

Last modified:

17/04/2026

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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS v3.1 Severity and Metrics:

Base Score: 5.30 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): Low