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CVE-2026-35030

Litellm authentication bypass

9.1 CRITICALEPSS 0.88%
  1. Published6 Apr 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Litellm< 1.83.0

Remediation

Fixed in
Litellm≥ 1.83.0

References

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Frequently asked

Is CVE-2026-35030 being actively exploited?

CVE-2026-35030 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.88%.

How severe is CVE-2026-35030?

CVE-2026-35030 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.88% probability of exploitation.

Which products are affected by CVE-2026-35030?

Affected products include Litellm.

How do I fix CVE-2026-35030?

Upgrade affected software to a fixed version, for example Litellm 1.83.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-35030 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.