CVE-2026-39413: lightrag-hku: JWT Algorithm Confusion Vulnerability

April 8, 2026 (updated April 27, 2026)

The LightRAG API is vulnerable to a JWT algorithm confusion attack where an attacker can forge tokens by specifying ‘alg’: ’none’ in the JWT header. Since the jwt.decode() call does not explicitly deny the ’none’ algorithm, a crafted token without a signature will be accepted as valid, leading to unauthorized access.

References

github.com/HKUDS/LightRAG
github.com/HKUDS/LightRAG/commit/728f2e54509d93e0a44f929c7f83f2c88d6d291b
github.com/HKUDS/LightRAG/security/advisories/GHSA-8ffj-4hx4-9pgf
github.com/advisories/GHSA-8ffj-4hx4-9pgf
nvd.nist.gov/vuln/detail/CVE-2026-39413

Code Behaviors & Features

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