Cyber Resilience

CVE-2025-56221

Critical

Published: 17 October 2025

Published
17 October 2025
Modified
27 October 2025
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0007 20.8th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-56221 is a critical-severity Improper Restriction of Excessive Authentication Attempts (CWE-307) vulnerability in Ascertia Signinghub. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked at the 20.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

A lack of rate limiting in the login mechanism of SigningHub v8.6.8 allows attackers to bypass authentication via a brute force attack.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
Why these techniques?

Lack of rate limiting on the authentication API enables brute force attacks (T1110), including password guessing, by allowing unlimited login attempts.

Affected Assets

ascertia
signinghub
≤ 8.6.8

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-307

This control directly enforces limits on consecutive invalid logon attempts and automatic response (e.g., lockout) to prevent brute-force exploitation of authentication mechanisms.

addresses: CWE-307

Specific conditions can include excessive failed attempts, triggering stronger authentication that restricts brute-force exploitation.

References