Description
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 (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. Fixed in v1.83.0.
Affected products
litellm: litellm
References7
- github.com/BerriAI/litellm/security/advisories/GHSA-jjhc-v7c2-5… MitigationVendor Advisory
- access.redhat.com/errata/RHSA-2026:13545
- access.redhat.com/errata/RHSA-2026:28960
- access.redhat.com/errata/RHSA-2026:30056
- access.redhat.com/security/cve/CVE-2026-35030
- bugzilla.redhat.com/show_bug.cgi?id=2455509
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35030…
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 4.0
-
9.4
CRITICAL
Score source: CNA
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 1% percentile: 51 · as of 12 November 2026
- CWE
- CWE-287CWE-222
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