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MantisBT Vulnerable to Denial-of-Service (DoS) via Excessive Note Length

Moderate severity GitHub Reviewed Published Nov 1, 2025 in mantisbt/mantisbt • Updated Nov 4, 2025

Package

composer mantisbt/mantisbt (Composer)

Affected versions

< 2.27.2

Patched versions

2.27.2

Description

A lack of server-side validation for note length in MantisBT allows attackers to permanently corrupt issue activity logs by submitting extremely long notes (tested with 4,788,761 characters). Once such a note is added:

Impact

  • The entire activity stream becomes unviewable (UI fails to render).
  • New notes cannot be displayed, effectively breaking all future collaboration on the issue.

Patches

Fixed in 2.27.2.

Workarounds

None

Credits

Thanks to Mazen Mahmoud (@TheAmazeng) for reporting the vulnerability.

References

@dregad dregad published to mantisbt/mantisbt Nov 1, 2025
Published to the GitHub Advisory Database Nov 3, 2025
Reviewed Nov 3, 2025
Published by the National Vulnerability Database Nov 4, 2025
Last updated Nov 4, 2025

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

Weaknesses

Allocation of Resources Without Limits or Throttling

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Learn more on MITRE.

CVE ID

CVE-2025-46556

GHSA ID

GHSA-r3jf-hm7q-qfw5

Source code

Credits

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