mapserver: MapServer is a system for developing web-based GIS applications
CVE-2026-33721 is fixed in mapserver on 1 platform, first by DEBIAN-CVE-2026-33721, released March 27, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| mapserver · Debian 12.15 (bookworm) | 8.0.0-3+deb12u1 | DEBIAN-CVE-2026-33721 | Mar 27, 2026 |
| mapserver · Debian 13.5 (trixie) | 8.4.0-4+deb13u2 | DEBIAN-CVE-2026-33721 | Mar 27, 2026 |
| mapserver · Debian 14 | 8.6.1-1 | DEBIAN-CVE-2026-33721 | Mar 27, 2026 |
| mapserver · opensuse-leap 16.0 | 8.6.1-bp160.1.1 | OPENSUSE-SU-2026:20476-1 | Nov 7, 2026 |
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