---
title: "CVE-2026-35030: LiteLLM: Authentication bypass via OIDC userinfo cache key collision"
url: https://erroneo.us/security/cve/CVE-2026-35030/
description: "CVE-2026-35030 (litellm (PyPI)): LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.83.0, when JWT…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-06
date_modified: 2026-07-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-35030"
kev: false
cvss: 9.4
epss: 0.00879
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-35030: LiteLLM: Authentication bypass via OIDC userinfo cache key collision

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.9% , percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes litellm (PyPI) < 1.83.0, fixed in 1.83.0 . Check your lockfile, including transitive dependencies.

## What it is

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.83.0, when JWT authentication is enabled (enablejwtauth: 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. Fixed in v1.83.0.

## Affected packages

- PyPI `litellm` < 1.83.0 → fixed: 1.83.0

## Affected products (CVE record)

- BerriAI litellm: < 1.83.0

## Severity

- GitHub_M CVSS 4.0: 9.4 `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`
- CISA-ADP CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- redhat-SADP CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 4.0: 9.4 `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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.88% probability of exploitation activity in the next 30 days; percentile 59.

## Sources

- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:13545)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:28960)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:30056)
- [GitHub Advisory GHSA-jjhc-v7c2-5hh6](https://github.com/advisories/GHSA-jjhc-v7c2-5hh6)
- [CVE.org record CVE-2026-35030](https://www.cve.org/CVERecord?id=CVE-2026-35030)
- [NVD entry CVE-2026-35030](https://nvd.nist.gov/vuln/detail/CVE-2026-35030)
- [github.com](https://github.com/BerriAI/litellm/security/advisories/GHSA-jjhc-v7c2-5hh6)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-35030)
- [RHBZ#2455509](https://bugzilla.redhat.com/show_bug.cgi?id=2455509)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35030.json)

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Source page: https://erroneo.us/security/cve/CVE-2026-35030/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt