Cyber Resilience

CVE-2026-42203

HighRCEUpdated

Published: 08 May 2026

Published
08 May 2026
Modified
30 June 2026
KEV Added
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Patch
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CVSS Score v4 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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 0.0037 29.3th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-42203 is a high-severity Improper Neutralization of Special Elements Used in a Template Engine (CWE-1336) vulnerability in Litellm Litellm. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 29.3th 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 LLM/Generative AI Risks risk domain.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability details

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.80.5 to before version 1.83.7, the POST /prompts/test endpoint accepted user-supplied prompt templates and rendered them without sandboxing. A crafted template could…

more

run arbitrary code inside the LiteLLM Proxy process. The endpoint only checks that the caller presents a valid proxy API key, so any authenticated user could reach it. Depending on how the proxy is deployed, this could expose secrets in the process environment (such as provider API keys or database credentials) and allow commands to be run on the host. This issue has been patched in version 1.83.7.

CWE(s)
CWE-1336CWE-94

AI Security AnalysisAI

AI Category
LLM Application Platforms
Risk Domain
LLM/Generative AI Risks
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: ai, llm, openai

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

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 →
T1059.006 Python Execution
Adversaries may abuse Python commands and scripts for execution.
attack.mitre.org →
Why these techniques?

Server-side template injection in public-facing proxy endpoint directly enables RCE via unsandboxed Python template rendering after API key auth.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

litellm
litellm
1.80.5 — 1.83.7

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-34 Non-modifiable Executable Programs
addresses: CWE-94

Makes persistent code injection into loaded programs impossible when the executable image itself resides on hardware-protected read-only media.

SC-44 Detonation Chambers
addresses: CWE-94

Dynamically generated code can be produced and executed inside the isolated chamber, preventing host compromise from code-injection payloads.

SI-10 Information Input Validation
addresses: CWE-94

Validates inputs used in dynamic code generation to block injected directives.

SI-16 Memory Protection
addresses: CWE-94

Directly prevents execution of attacker-supplied code written into data memory regions.

References