Vulnerability in Ascertia Signinghub

CVE-2025-56221

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

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (46.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 46.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-56221: held from 0.006 to 0.006.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-56221?
CVE-2025-56221 is a critical-severity vulnerability in Ascertia Signinghub, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2025-10-17.
How severe is CVE-2025-56221?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-56221 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.