CVE-2026-33721 — MapServer has heap buffer overflow in SLD `Categorize` Threshold parsing
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 Laye…
Published: 2026-03-27 · CVSS: 5.3 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7