Cyber Resilience

CVE-2025-54321

Critical

Published: 18 November 2025

Published
18 November 2025
Modified
20 November 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 0.0003 8.1th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-54321 is a critical-severity Improper Control of Interaction Frequency (CWE-799) vulnerability in Ascertia Signinghub. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Email Bombing (T1667); ranked at the 8.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

In Ascertia SigningHub through 8.6.8, there is a lack of rate limiting on the reset password function, leading to an email bombing vulnerability. An authenticated attacker can exploit this by automating reset password requests.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1667 Email Bombing Impact
Adversaries may flood targeted email addresses with an overwhelming volume of messages.
Why these techniques?

The vulnerability lacks rate limiting on password reset requests, enabling authenticated attackers to automate requests and perform email bombing (T1667) by flooding target user mailboxes and overwhelming mail servers.

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-799

The control requires defining frequency, timing, and approval for security interactions, directly addressing uncontrolled interaction rates.

addresses: CWE-799

Allocation policies inherently restrict interaction frequency, reducing the impact of excessive requests.

addresses: CWE-799

Spam protection explicitly controls interaction frequency by detecting and acting on bulk unsolicited messages from external sources.

References