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Medium

LiteLLM Proxy has server-side request forgery via the `user_config` request parameter

  • Disclosed: 17.09.2026
  • Updated: 11.10.2026 15:18

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).

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) litellm < 1.83.9 1.83.9

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
Weakness (CWE)
CWE-918
Platform
Python (PyPI)
Package
litellm
Disclosed
17.09.2026
Updated
11.10.2026 15:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-4070 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-hx8v-g79f-8w5f - CC BY 4.0

Vulnerability history: litellm

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (42) in the archive
Total entries
42
First → latest
04.2024 09.2026
Without a fix
14
Exploited in attacks
3

Severity breakdown

  • Critical 7
  • High 17
  • Medium 8
  • Low 9
  • Unrated 1

Disclosures per year

Severity:
  1. LiteLLM Proxy has server-side request forgery via the `user_config` request parameter this entry
    Medium CVE-2026-59823 < 1.83.9 1.83.9
  2. LiteLLM vulnerable to server-side template injection in the /prompts/test endpoint
    Critical · 9.8 CVE-2026-37004 < 1.83.7 1.83.7
  3. LiteLLM: MCP Authentication Bypass via OAuth2 Passthrough Fallback
    High Exploited in attacks CVE-2026-59822 < 1.84.0 1.84.0
  4. LiteLLM: Authentication Bypass via Host Header Injection
    Critical · 9.8 CVE-2026-49468 < 1.84.0 1.84.0
  5. LiteLLM allows a user to modify their own user_role via the /user/update endpoint
    High · 8.8 CVE-2026-47102 < 1.83.10 1.83.10
  6. LiteLLM allows an authenticated internal_user to create API keys with access to routes that their role does not permit
    High · 8.8 CVE-2026-47101 < 1.83.14 1.83.14
  7. LiteLLM has a sandbox escape in custom-code guardrail
    High · 8.8 CVE-2026-40217 >= 1.81.8, < 1.83.10 1.83.10
  8. LiteLLM: Authenticated command execution via MCP stdio test endpoints
    High · 8.8 Exploited in attacks CVE-2026-42271 >= 1.74.2, < 1.83.7 1.83.7
  9. LiteLLM has SQL Injection in Proxy API key verification
    Critical · 9.8 Exploited in attacks CVE-2026-42208 >= 1.81.16, < 1.83.7 1.83.7
  10. LiteLLM: Server-Side Template Injection in /prompts/test endpoint
    High CVE-2026-42203 >= 1.80.5, < 1.83.7 1.83.7
  11. LiteLLM: Password hash exposure and pass-the-hash authentication bypass
    High ghsa-69x8-hrgq-fjj8 < 1.83.0 1.83.0
  12. LiteLLM: Authentication bypass via OIDC userinfo cache key collision
    Critical CVE-2026-35030 < 1.83.0 1.83.0
  13. LiteLLM: Privilege escalation via unrestricted proxy configuration endpoint
    High CVE-2026-35029 < 1.83.0 1.83.0
  14. Two LiteLLM versions published containing credential harvesting malware
    Critical ghsa-5mg7-485q-xm76 >= 1.82.7, <= 1.82.8 no fix
  15. LiteLLM Has an Improper Authorization Vulnerability
    High · 8.1 CVE-2025-0628 < 1.61.15 1.61.15
  16. LiteLLM Has a Leakage of Langfuse API Keys
    High · 7.5 CVE-2025-0330 <= 1.52.1 no fix
  17. LiteLLM Reveals Portion of API Key via a Logging File
    High · 7.5 CVE-2024-9606 < 1.44.12 1.44.12
  18. LiteLLM Vulnerable to Denial of Service (DoS) via Crafted HTTP Request
    High · 7.5 CVE-2024-8984 < 1.56.2 1.56.2
  19. LiteLLM Vulnerable to Remote Code Execution (RCE)
    High · 8.8 CVE-2024-6825 >= 1.40.3.dev2, <= 1.40.12 no fix
  20. LiteLLM Vulnerable to Denial of Service (DoS)
    High · 7.5 CVE-2024-10188 < 1.53.1.dev1 1.53.1.dev1
Show more (5) Showing 20 of 25

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