Cyber Resilience

CVE-2025-6518

Published
23 June 2025
Modified
17 June 2026
CVSS Score v4 2.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0033 25th percentile
Risk Priority 26 floored blend · peak EPSS

Summary

CVE-2025-6518 is a low-severity Incomplete Filtering of Special Elements (CWE-791) vulnerability. Its CVSS base score is 2.1 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Template Injection (T1221); ranked at the 25th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as LLM Application Platforms; in the Data-Related Vulnerabilities risk domain.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A vulnerability was found in PySpur-Dev pyspur up to 0.1.18. It has been classified as critical. Affected is the function SingleLLMCallNode of the file backend/pyspur/nodes/llm/single_llm_call.py of the component Jinja2 Template Handler. The manipulation of the argument user_message leads to improper…

more

neutralization of special elements used in a template engine. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.

CWE(s)
CWE-791CWE-1336

AI Security AnalysisAI

AI Category
LLM Application Platforms
Risk Domain
Data-Related Vulnerabilities
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: llm

Related Threats

MITRE ATT&CK Enterprise Techniques

T1221 Template Injection Stealth
Adversaries may create or modify references in user document templates to conceal malicious code or force authentication attempts.
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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-2040Shared CWE-1336, CWE-791
CVE-2026-3725Shared CWE-1336, CWE-791
CVE-2026-9498Shared CWE-1336, CWE-791
CVE-2026-5559Shared CWE-1336, CWE-791
CVE-2026-6984Shared CWE-1336, CWE-791
CVE-2026-3714Shared CWE-1336, CWE-791
CVE-2026-8740Shared CWE-1336, CWE-791
CVE-2025-14731Shared CWE-1336, CWE-791
CVE-2026-2969Shared CWE-1336, CWE-791
CVE-2025-5325Shared CWE-1336, CWE-791

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.3.2
  • V1.3.7
  • V1.3.10

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and static analysis can discover missing neutralization of template directives.

SI-10 Information Input Validation good match

Input validation directly requires complete filtering of special elements on received data before further processing or forwarding.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles require use of safe templating APIs and proper escaping of external input.

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 complete input filtering and sanitization to prevent this weakness.

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 and acceptance can detect incomplete filtering but does not itself implement the filtering.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle processes include validation activities that reduce the likelihood of CWE-791 but do not specify the control itself.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for input validation and sanitization that directly mitigates incomplete special-element filtering.

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

Secure system architecture and engineering principles require defensive design patterns that prevent unfiltered data from reaching downstream components.

A.8.28 Secure coding partial match
prevents

Secure coding standards mandate complete filtering and escaping of special elements, directly eliminating CWE-791.

References