CVE-2026-35030
LiteLLM has an authentication bypass via OIDC userinfo cache key collision
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
LiteLLM has an authentication bypass via OIDC userinfo cache key collision
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.
- Record
CVE-2026-35030- CVSS 4.0
- 9.4 Critical
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 - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-287, CWE-222
- Updated
- 2026-11-02
EUVDEUVD-2026-19372
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.
- Record
EUVD-2026-19372- CVSS 4.0
- 9.4 Critical
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-jjhc-v7c2-5hh6
LiteLLM: Authentication bypass via OIDC userinfo cache key collision
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.
- Record
GHSA-jjhc-v7c2-5hh6- CVSS 4.0
- 9.4 Critical
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 - Weakness
- CWE-287
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-35030- CVSS 4.0
- 9.4 Critical
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 - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-287, CWE-222
- Updated
- 2026-11-02
OSV
LiteLLM has an authentication bypass via OIDC userinfo cache key collision
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.
- Record
CVE-2026-35030- CVSS 4.0
- 9.4 Critical
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 - Weakness
- CWE-287
- Updated
- 2026-11-02
OSVGHSA-jjhc-v7c2-5hh6
LiteLLM: Authentication bypass via OIDC userinfo cache key collision
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.
- Record
GHSA-jjhc-v7c2-5hh6- CVSS 4.0
- 9.4 Critical
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 - Weakness
- CWE-287
- Updated
- 2026-11-02
OSVPYSEC-2026-390
LiteLLM: Authentication bypass via OIDC userinfo cache key collision
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.
- Record
PYSEC-2026-390- CVSS 4.0
- 9.4 Critical
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 - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
litellmPyPI |
before 1.83.0 | 1.83.0 |
litellmPyPI |
before 1.83.0, plus listed versions 0.1.00.1.10.1.20.1.2010.1.202 Show 45 moreShow less0.1.2030.1.2040.1.2050.1.2060.1.2070.1.2080.1.2090.1.2100.1.2110.1.2120.1.2130.1.2140.1.2150.1.2160.1.2170.1.2180.1.2190.1.2200.1.2210.1.2220.1.2230.1.2240.1.2250.1.2260.1.2270.1.2280.1.2290.1.22910.1.2300.1.2310.1.2320.1.2330.1.2340.1.2350.1.2360.1.2370.1.2380.1.30.1.310.1.320.1.3300.1.3310.1.340.1.3410.1.343 |
1.83.0 |
litellmPyPI |
before 1.83.0, plus listed versions 0.1.00.1.10.1.20.1.2010.1.202 Show 45 moreShow less0.1.2030.1.2040.1.2050.1.2060.1.2070.1.2080.1.2090.1.2100.1.2110.1.2120.1.2130.1.2140.1.2150.1.2160.1.2170.1.2180.1.2190.1.2200.1.2210.1.2220.1.2230.1.2240.1.2250.1.2260.1.2270.1.2280.1.2290.1.22910.1.2300.1.2310.1.2320.1.2330.1.2340.1.2350.1.2360.1.2370.1.2380.1.30.1.310.1.320.1.3300.1.3310.1.340.1.3410.1.343 |
1.83.0 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | learner202649/CVE-2026-35030-PoC | 2026-05-19 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-35030 is a critical vulnerability (CVSS 9.4) in Berriai Litellm, published April 3, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.64%, the 50th percentile. Fixed in litellm 1.83.0.
References
github.com/BerriAI/litellm/security/advisories/GHSA-jjhc-v7c2-5hh6
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.json
Left out here: 1,728 versions. The JSON record has them.