CVE-2026-59823
mediumpriority · track · 0EPSS 0.004 · 38 %ileUSEPSS · scored 2026-10-27
LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.83.9, an authenticated LiteLLM Proxy caller with a valid virtual key can place api_base inside the user_config request body to bypass is_request_body_safe, which blocks top-level api_base and base_url but previously did not inspect or reject user_config. Because user_config constructs the outbound router, the nested destination redirects a server-side request to an internal or external host selected by the caller and can expose endpoints the caller cannot otherwise access. This issue is fixed in version 1.83.9.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.3–5.3
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-hx8v-g79f-8w5fLiteLLM Proxy has server-side request forgery via the `user_config` request parameter2026-09-17ghsa · osvUS
### Summary A server-side request forgery in LiteLLM Proxy lets an authenticated caller redirect the proxy's outbound request to a host of their choosing by smuggling an `api_base` inside the `user_config` request body, bypassing the existing parameter guard. ### Details LiteLLM Proxy validates request bodies with `is_request_body_safe`, which blocks the `api_base` and `base_url` parameters but does not cover `user_config`. The `user_config` object is used to build the outbound router for a request, so a caller can place an `api_base` inside it and reach an arbitrary host. The guard only inspected the two top-level keys, so the same `api_base` nested inside `user_config` was never checked. Exploitation requires a valid virtual key. ### Impact An authenticated caller can make the proxy issue server-side requests to internal or external hosts of their choosing, reaching endpoints the caller cannot otherwise access. ### Affected / Patched Affected: `<= 1.83.8` Patched: `1.83.9` ### Remediation Upgrade to 1.83.9 or later (released 2026-04-17).
- PYSEC-2026-4070LiteLLM Proxy has server-side request forgery via the `user_config` request parameter2026-10-01vendor · osvUS
### Summary A server-side request forgery in LiteLLM Proxy lets an authenticated caller redirect the proxy's outbound request to a host of their choosing by smuggling an `api_base` inside the `user_config` request body, bypassing the existing parameter guard. ### Details LiteLLM Proxy validates request bodies with `is_request_body_safe`, which blocks the `api_base` and `base_url` parameters but does not cover `user_config`. The `user_config` object is used to build the outbound router for a request, so a caller can place an `api_base` inside it and reach an arbitrary host. The guard only inspected the two top-level keys, so the same `api_base` nested inside `user_config` was never checked. Exploitation requires a valid virtual key. ### Impact An authenticated caller can make the proxy issue server-side requests to internal or external hosts of their choosing, reaching endpoints the caller cannot otherwise access. ### Affected / Patched Affected: `<= 1.83.8` Patched: `1.83.9` ### Remediation Upgrade to 1.83.9 or later (released 2026-04-17).
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (3) nvd
External citations — patches, advisories, analysis.
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan