---
title: "CVE-2026-61740: LightRAG is Vulnerable to Authentication Bypass: hardcoded DEFAULT_TOKEN_SECRET and public /auth-status defeat LIGHTRAG_API_KEY protection"
url: https://erroneo.us/security/cve/CVE-2026-61740/
description: "CVE-2026-61740 (lightrag-hku (PyPI)): LightRAG provides simple and fast retrieval-augmented generation. Prior to 1.5.4, when LightRAG is deployed with…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-15
date_modified: 2026-07-20
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-61740"
kev: false
cvss: 9.3
epss: 0.00662
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-61740: LightRAG is Vulnerable to Authentication Bypass: hardcoded DEFAULT_TOKEN_SECRET and public /auth-status defeat LIGHTRAG_API_KEY protection

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.7% , percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes lightrag-hku (PyPI) < 1.5.4, fixed in 1.5.4 . Check your lockfile, including transitive dependencies.

## What it is

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

## Affected packages

- PyPI `lightrag-hku` < 1.5.4 → fixed: 1.5.4

## Affected products (CVE record)

- HKUDS LightRAG: < 1.5.4

## Severity

- GitHub_M CVSS 4.0: 9.3 `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`
- GitHub CVSS 4.0: 9.3 `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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.66% probability of exploitation activity in the next 30 days; percentile 51.

## Sources

- [GitHub Advisory GHSA-f4vv-55c2-5789](https://github.com/advisories/GHSA-f4vv-55c2-5789)
- [CVE.org record CVE-2026-61740](https://www.cve.org/CVERecord?id=CVE-2026-61740)
- [NVD entry CVE-2026-61740](https://nvd.nist.gov/vuln/detail/CVE-2026-61740)
- [github.com](https://github.com/HKUDS/LightRAG/security/advisories/GHSA-f4vv-55c2-5789)
- [github.com](https://github.com/HKUDS/LightRAG/pull/3319)
- [github.com](https://github.com/HKUDS/LightRAG/commit/f7819aa3a49a9d8d92eed8251d82d6ebcafa8cba)
- [github.com](https://github.com/HKUDS/LightRAG/releases/tag/v1.5.4)

---
Source page: https://erroneo.us/security/cve/CVE-2026-61740/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt