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VulnerabilityPublished

CVE-2025-56221: SigningHub · Improper Restriction of Excessive Authentication Attempts

Affects SigningHubSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 11:42 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 Oct 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
GitHubsaykino/SigningHubpkg:github/saykino/SigningHubOther threatsAffected
  • =8.6.8
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate the risk posed by CVE-2025-56221, organizations should implement the following specific measures: 1) Apply any available patches or updates from the vendor as soon as they are released. 2) If patches are not yet available, deploy compensating controls such as web application firewalls (WAFs) configured to detect and block excessive login attempts from single IP addresses or user accounts. 3) Enforce strong password policies and encourage or require multi-factor authentication (MFA) to reduce the risk of successful brute force attacks. 4) Implement account lockout mechanisms after a defined number of failed login attempts to prevent unlimited guessing. 5) Monitor authentication logs for unusual patterns indicative of brute force or credential stuffing attacks and respond promptly. 6) Conduct regular security awareness training to ensure users recognize phishing attempts that could lead to credential compromise. 7) Consider network segmentation and least privilege principles to limit the impact of compromised accounts. These measures go beyond generic advice by focusing on compensating controls and proactive monitoring in the absence of immediate patches.

Description

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

References

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