Vulnerability Report

CVE-2026-45104

Title: MapServer Null Pointer Dereference in SLD Parsing

Memory Corruption

Proof Of Concept

No public PoC currently indexed for CVE-2026-45104.

CWE Category CWE-129

Published Date May 27, 2026

Modified Date Jun 02, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.05%

Vulnerability Summary

CVE-2026-45104: 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.

Impacted Vendors

university_of_minnesota 1

osgeo 1

Reference Links

https://github.com/MapServer/MapServer/security/advisories/GHSA-4h8g-378q-r75m

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-45104 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

June 02, 2026 MODIFIED

Vulnerability data updated via NVD.

May 29, 2026 MODIFIED

Vulnerability data updated via NVD.

May 27, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.