Improper Restriction of Excessive Authentication Attempts vulnerability in CIRCL Vulnerability-Lookup

published 2025-12-08 11 mo ago modified 2026-10-14 25 d ago also EUVD-2025-201703

cvss: 8.1; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits: 0; none known

In affected versions, vulnerability-lookup did not track or limit failed One-Time Password (OTP) attempts during Two-Factor Authentication (2FA) verification. An attacker who already knew or guessed a valid username and password could submit an arbitrary number of OTP codes without causing the account to be locked or generating any specific alert for administrators.

This lack of rate-limiting and lockout on OTP failures significantly lowers the cost of online brute-force attacks against 2FA codes and increases the risk of successful account takeover, especially if OTP entropy is reduced (e.g. short numeric codes, user reuse, or predictable tokens). Additionally, administrators had no direct visibility into accounts experiencing repeated 2FA failures, making targeted attacks harder to detect and investigate.

The patch introduces a persistent failed_otp_attempts counter on user accounts, locks the user after 5 invalid OTP submissions, resets the counter on successful verification, and surfaces failed 2FA attempts in the admin user list. This enforces an account lockout policy for OTP brute-force attempts and improves monitoring capabilities for suspicious 2FA activity.This issue affects Vulnerability-Lookup: before 2.18.0.

Patch / fix

fixed in 1

CIRCL Vulnerability-Lookup 2.18.0

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 11 mo ago (2025-12-08)

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
CNA	4.0	8.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

CIRCL Vulnerability-Lookup

Classification

Weakness

CWE-307 Improper Restriction of Excessive Authentication Attempts

References

vulnerability.circl.lu /vuln/gcve-1-2025-0033
vendor-advisory

Sources

CVE List CVE-2025-42615
NVD CVE-2025-42615

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary