Improper Verification of Cryptographic Signature Affecting litellm package, versions <1.89.0-r4


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LITELLM-17680752
  • published30 Jun 2026
  • disclosed28 May 2026

Introduced: 28 May 2026

CVE-2026-48523  (opens in a new tab)
CWE-347  (opens in a new tab)

How to fix?

Upgrade Chainguard litellm to version 1.89.0-r4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream litellm package and not the litellm package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0.

CVSS Base Scores

version 3.1