Vulnerability details
CVE-2026-45104
MapServer MapServer
MapServer: NULL pointer dereference in SLD `<ElseFilter>` rule parsing reachable via WMS `SLD_BODY`
CVSS 3.1
7.5High
Official description
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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| MapServer | MapServer | >= 6.4.0, < 8.6.3 | CVEProject cvelistV5 (CNA) |
References and advisories
1- https://github.com/MapServer/MapServer/security/advisories/GHSA-4h8g-378q-r75m x_refsource_CONFIRM
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Details
- Published
- 2026-05-27
- Last updated
- 2026-06-01
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
0.32%
Probability of exploitation in 30 days
25.2%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-129Improper Validation of Array Index
- CWE-476NULL Pointer Dereference