What’s Vulnerable › Vulnerabilities

CVE-2025-46556: MantisBT is Vulnerable to Denial-of-Service (DoS) attack via Excessive Note Length

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-11-04 · updated 2026-10-19
• Weakness: CWE-770

Description

Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.27.1 and below allow attackers to permanently corrupt issue activity logs by submitting extremely long notes (tested with 4,788,761 characters) due to a lack of server-side validation of note length. Once such a note is added, the activity stream UI fails to render; therefore, new notes cannot be displayed, effectively breaking all future collaboration on the issue. This issue is fixed in version 2.27.2.

Affected products

• mantisbt: before 2.27.2 — fixed in 2.27.2

How to fix

Upgrade to a fixed version: mantisbt 2.27.2. Check the vendor advisory for mitigations.

References

• https://github.com/mantisbt/mantisbt/commit/c99a41272532ba49b5c8dccb7797afead9864234
• https://github.com/mantisbt/mantisbt/commit/d5cec6bffb44d54bd412c186b9baa409b1aa4238
• https://github.com/mantisbt/mantisbt/commit/e9119c68b4a0eaa0bbde3deb121e81f5f7157361
• https://github.com/mantisbt/mantisbt/security/advisories/GHSA-r3jf-hm7q-qfw5

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