CVE-2026-59823: Litellm LiteLLM Proxy Has Server-side Request Vulnerability

MODERATE
Advisory Identifier: GHSA-hx8v-g79f-8w5f
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CWE-918
Published
Advisory Summary

CVE-2026-59823 is a MODERATE litellm proxy has server-side request vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affecting Litellm libraries in the PyPI ecosystem. The issue involves litellm proxy has server-side request forgery via the `user_config` request parameter. Remediation is available by upgrading affected packages to version 1.83.9.

CVE-2026-59823 at a Glance

CVE Identifier CVE-2026-59823
GHSA Identifier GHSA-hx8v-g79f-8w5f
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-918: Server-Side Request Forgery (SSRF)
Affected Product Litellm
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-59823

To remediate this vulnerability, upgrade all affected Litellm dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

litellm fixed: 1.83.9 
pip install litellm>=1.83.9
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show litellm

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-59823, inspect your installed packages using pip:

pip show litellm

Analyze the terminal output to locate any version of Litellm in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.83.9), your application is affected.

Note: The pip show litellm command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-918: Server-Side Request Forgery (SSRF), where the web server receives a url or similar request from an upstream component and retrieves the contents of this url, but it does not sufficiently ensure that the request is being sent to the expected destination. In Litellm, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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).

CVE-2026-59823 Affected Litellm Versions

1 component(s)
Fixed Versions:
1.83.9
Product / Package Ecosystem Affected Versions Fixed Version
litellm
pypi/litellm
PyPI
< 1.83.9
1.83.9

References

GitHub Advisory / Wiki ADVISORY
https://github.com/BerriAI/litellm/security/advisories/GHSA-hx8v-g79f-8w5f
NVD — CVE-2026-59823 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59823
Litellm Source Repository REPOSITORY
https://github.com/BerriAI/litellm/pull/25827
Security Fix Commit FIX COMMIT
https://github.com/BerriAI/litellm/commit/47214be317f45a2d2ac08258362e0481411eb427
Litellm Source Repository REPOSITORY
https://github.com/BerriAI/litellm

Frequently Asked Questions

What is CVE-2026-59823?
CVE-2026-59823 is a security vulnerability in Litellm involving LiteLLM Proxy has server-side request forgery via the `user_config` request parameter under CWE-918: Server-Side Request Forgery (SSRF).
Which Litellm versions are affected?
Affected versions include releases prior to 1.83.9 across affected packages: litellm.
What version fixes CVE-2026-59823?
Upgrading to 1.83.9 (or the latest patched release for your respective branch) resolves the vulnerability.
Is litellm affected?
Yes, litellm is affected in releases prior to 1.83.9. Upgrade your dependency to 1.83.9 or later.
What CWE is associated with CVE-2026-59823?
CVE-2026-59823 is classified under CWE-918: Server-Side Request Forgery (SSRF) (The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.).
How can I check PyPI dependencies for CVE-2026-59823?
Run the dependency tree command: 'pip show litellm'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hx8v-g79f-8w5f",
  "modified" : "2026-09-17T14:51:21Z",
  "published" : "2026-09-17T14:51:21Z",
  "aliases" : [ "CVE-2026-59823" ],
  "summary" : "LiteLLM Proxy has server-side request forgery via the `user_config` request parameter",
  "details" : "### Summary\nA server-side request forgery in LiteLLM Proxy lets an authenticated caller redirect the\nproxy's outbound request to a host of their choosing by smuggling an `api_base` inside the\n`user_config` request body, bypassing the existing parameter guard.\n\n### Details\nLiteLLM Proxy validates request bodies with `is_request_body_safe`, which blocks the\n`api_base` and `base_url` parameters but does not cover `user_config`. The `user_config`\nobject is used to build the outbound router for a request, so a caller can place an\n`api_base` inside it and reach an arbitrary host. The guard only inspected the two\ntop-level keys, so the same `api_base` nested inside `user_config` was never checked.\n\nExploitation requires a valid virtual key.\n\n### Impact\nAn authenticated caller can make the proxy issue server-side requests to internal or\nexternal hosts of their choosing, reaching endpoints the caller cannot otherwise access.\n\n### Affected / Patched\nAffected: `<= 1.83.8`\nPatched: `1.83.9`\n\n### Remediation\nUpgrade to 1.83.9 or later (released 2026-04-17).",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "litellm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.83.9"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.83.8"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/BerriAI/litellm/security/advisories/GHSA-hx8v-g79f-8w5f"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-59823"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/BerriAI/litellm/pull/25827"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/BerriAI/litellm/commit/47214be317f45a2d2ac08258362e0481411eb427"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/BerriAI/litellm"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-918" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-17T14:51:21Z",
    "nvd_published_at" : "2026-09-16T19:17:21Z"
  }
}