CVE-2026-35030: LiteLLM Authentication Bypass Vulnerability

CRITICAL
Advisory Identifier: GHSA-jjhc-v7c2-5hh6
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CWE-287
Published
Advisory Summary

CVE-2026-35030 is a CRITICAL authentication bypass vulnerability (CWE-287: Improper Authentication) affecting LiteLLM libraries in the PyPI ecosystem. The issue involves authentication bypass via oidc userinfo cache key collision. Remediation is available by upgrading affected packages to version 1.83.0.

CVE-2026-35030 at a Glance

CVE Identifier CVE-2026-35030
GHSA Identifier GHSA-jjhc-v7c2-5hh6
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-287: Improper Authentication
Affected Product LiteLLM
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-35030

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: 1.83.0 
pip install litellm>=1.83.0
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-2026-35030, 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 1.83.0), 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-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. 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

### Impact When JWT authentication is enabled (`enable_jwt_auth: true`), the OIDC userinfo cache uses `token[:20]` as the cache key. JWT headers produced by the same signing algorithm generate identical first 20 characters. This configuration option is not enabled by default. **Most instances are not affected.** An unauthenticated attacker can craft a token whose first 20 characters match a legitimate user's cached token. On cache hit, the attacker inherits the legitimate user's identity and permissions. This affects deployments with JWT/OIDC authentication enabled. ### Patches Fixed in v1.83.0. The cache key now uses the full hash of the JWT token. ### Workarounds Disable OIDC userinfo caching by setting the cache TTL to 0, or disable JWT authentication entirely.

CVE-2026-35030 Affected LiteLLM Versions

1 component(s)
Fixed Versions:
1.83.0
Product / Package Ecosystem Affected Versions Fixed Version
litellm
pypi/litellm
PyPI
< 1.83.0
1.83.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/BerriAI/litellm/security/advisories/GHSA-jjhc-v7c2-5hh6
NVD — CVE-2026-35030 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35030
LiteLLM Source Repository REPOSITORY
https://github.com/BerriAI/litellm

Frequently Asked Questions

What is CVE-2026-35030?
CVE-2026-35030 is a security vulnerability in LiteLLM involving Authentication bypass via OIDC userinfo cache key collision under CWE-287: Improper Authentication.
Which LiteLLM versions are affected?
Affected versions include releases prior to 1.83.0 across affected packages: litellm.
What version fixes CVE-2026-35030?
Upgrading to 1.83.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is litellm affected?
Yes, litellm is affected in releases prior to 1.83.0. Upgrade your dependency to 1.83.0 or later.
What CWE is associated with CVE-2026-35030?
CVE-2026-35030 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check PyPI dependencies for CVE-2026-35030?
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-jjhc-v7c2-5hh6",
  "modified" : "2026-04-06T23:40:39Z",
  "published" : "2026-04-03T21:59:50Z",
  "aliases" : [ "CVE-2026-35030" ],
  "summary" : "LiteLLM: Authentication bypass via OIDC userinfo cache key collision",
  "details" : "###  Impact\n\nWhen JWT authentication is enabled (`enable_jwt_auth: true`), the OIDC userinfo cache uses `token[:20]` as the cache key. JWT headers produced by the same signing algorithm generate identical first 20 characters.\n\nThis configuration option is not enabled by default. **Most instances are not affected.**\n\nAn unauthenticated attacker can craft a token whose first 20 characters match a legitimate user's cached token. On cache hit, the attacker inherits the legitimate user's identity and permissions. This affects deployments with JWT/OIDC authentication enabled.\n\n###  Patches\n\nFixed in v1.83.0. The cache key now uses the full hash of the JWT token.\n\n###  Workarounds\n\nDisable OIDC userinfo caching by setting the cache TTL to 0, or disable JWT authentication entirely.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "litellm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.83.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/BerriAI/litellm/security/advisories/GHSA-jjhc-v7c2-5hh6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-35030"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/BerriAI/litellm"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-03T21:59:50Z",
    "nvd_published_at" : "2026-04-06T17:17:12Z"
  }
}