CVE-2026-39413 MEDIUM

CVE-2026-39413: LightRAG has a JWT Algorithm Confusion Vulnerability in LightRAG API

Vendor Hkuds
Product LightRAG
Weakness CWE-347
Published April 8, 2026
Last update April 22, 2026

CVSS base score

4.2/10
Attack vector Network
Attack complexity High
Privileges required High
User interaction Required
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N

What the vulnerability does

01Description

LightRAG provides simple and fast retrieval-augmented generation. Prior to 1.4.14, 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. This vulnerability is fixed in 1.4.14.

Key dates

02Disclosure timeline

April 8, 2026 CVE published
April 22, 2026 Record updated