RCE in Berriai Litellm
CVE-2026-42203
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 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.
EPSS: 0.004 (30.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Berriai Litellm — versions >= 1.80.5, < 1.83.7
- Litellm
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Mitigation, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-42203?
- CVE-2026-42203 is a high-severity vulnerability in Berriai Litellm, classified under Improper Neutralization of Special Elements Used in a Template Engine. CVSS score: 8.8/10. Published 2026-05-08.
- How severe is CVE-2026-42203?
- High severity. CVSS v3 base score is 8.8 out of 10.
- Is CVE-2026-42203 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.