Cyber Resilience

CVE-2026-45104

Memory Safety in Osgeo Mapserver 6.4.0 – 8.6.3

Public PoCMemory Safety
Published
27 May 2026
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0032 25th percentile
Risk Priority 57 floored blend · peak EPSS

Summary

CVE-2026-45104 is a high-severity Improper Validation of Array Index (CWE-129) vulnerability in Osgeo Mapserver. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 25th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 InjectionA10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-129CWE-476

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-33721Same product: Osgeo Mapserver
CVE-2025-59431Same product: Osgeo Mapserver
CVE-2026-42030Same product: Osgeo Mapserver
CVE-2026-8088Same vendor: Osgeo
CVE-2026-8213Same vendor: Osgeo
CVE-2026-8084Same vendor: Osgeo
CVE-2026-8212Same vendor: Osgeo
CVE-2025-29480Same vendor: Osgeo
CVE-2026-49014Same vendor: Osgeo
CVE-2026-8087Same vendor: Osgeo

Affected Assets

osgeo
mapserver
6.4.0 — 8.6.3

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation (including static analysis) directly finds null-dereference bugs before deployment.

SA-15 Development Process, Standards, and Tools partial match

Documented development standards and tools can enforce null-safety rules and safe pointer usage.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles can mandate defensive coding such as explicit null checks before dereference.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and bounds checking that prevent improper array indexing.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect out-of-bounds array access but does not prevent the weakness by itself.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and bounds checking that directly prevents improper array indexing.

A.8.26 Application security requirements partial match
prevents

Application security requirements include validation of untrusted input used for indexing or addressing memory structures.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage defensive coding patterns that reduce index-related vulnerabilities.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly require bounds checking and validation of array indices derived from untrusted data.

References