EUVD-2026-32631CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2DescriptionNVD
MapServer is a system for developing web-based GIS applications. From 6.4.0 to before 8.6.3, msSLDParseUserStyle always calls _SLDApplyRuleValues(psRule, psLayer, 1); for any <Rule> carrying <ElseFilter/> - it assumes msSLDParseRule added one class. When the rule has no symbolizer (a structurally valid SLD), msSLDParseRule adds zero, and _SLDApplyRuleValues ends up indexing _class[-1], resulting in a NULL pointer dereference. A 200-byte well-formed SLD via the WMS SLD_BODY= parameter is enough to trigger this, no auth required. This vulnerability is fixed in 8.6.3.
AnalysisAI
Denial of service in MapServer 6.4.0 through 8.6.2 allows remote unauthenticated attackers to crash the server by submitting a small well-formed SLD document via the WMS SLD_BODY= parameter. The flaw is a NULL pointer dereference reached when an SLD <Rule> carries <ElseFilter/> but defines no symbolizer, causing the styling code to index a class array at position -1. …
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RemediationAI
Within 24 hours: identify and inventory all MapServer deployments and document versions in use. Within 7 days: upgrade all instances running versions 6.4.0-8.6.2 to MapServer 8.6.3 or later. …
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