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Medium

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

  • Disclosed: 03.11.2025
  • Updated: 11.10.2026 10:22

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.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package mantisbt/mantisbt < 2.27.2 2.27.2

References

CVSS score 6.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-770
Platform
Composer
Package
mantisbt/mantisbt
Disclosed
03.11.2025
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-r3jf-hm7q-qfw5 - CC BY 4.0

Vulnerability history: mantisbt/mantisbt

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (74) in the archive
Total entries
74
First → latest
04.2022 07.2026
Without a fix
2
Exploited in attacks
0

Severity breakdown

  • Critical 4
  • High 20
  • Medium 49
  • Low 1

Disclosures per year

Severity:
  1. MantisBT: Stored XSS in print_all_bug_page_word.php
    High CVE-2026-62944 < 2.28.4 2.28.4
  2. MantisBT: Reflected XSS in admin/install.php via unescaped printf
    Critical CVE-2026-52881 < 2.28.4 2.28.4
  3. MantisBT: Reflected XSS in admin/install.php
    Critical CVE-2026-52847 < 2.28.4 2.28.4
  4. MantisBT: Remote Code Execution via eval() Class Hoisting in adm_config_set.php
    High CVE-2026-49273 >= 1.3.0, < 2.28.4 2.28.4
  5. MantisBT: SOAP API Authentication Bypass with Privilege Escalation to Administrator
    Critical CVE-2026-47156 < 2.28.4 2.28.4
  6. MantisBT: SQL Injection via history_order Configuration Value
    High CVE-2026-47142 < 2.28.4 2.28.4
  7. MantisBT Vulnerable to Stored XSS in File Download
    High CVE-2026-44657 < 2.28.2 2.28.2
  8. MantisBT has Stored XSS on Move Attachments Admin Page
    High CVE-2026-44655 >= 1.3.0, < 2.28.2 2.28.2
  9. MantisBT has a Private Bugnote Attachment Content Leak via REST API
    High CVE-2026-42071 >= 2.23.0, < 2.28.2 2.28.2
  10. MantisBT is Vulnerable to Stored XSS in Saved-Filter Owner Column
    High CVE-2026-40607 >= 2.1.0, < 2.28.2 2.28.2
  11. MantisBT has a Content Security Policy bypass via attachments
    High CVE-2026-40597 < 2.28.2 2.28.2
  12. MantisBT is Vulnerable to XSS leading to account takeover via updating a user's font family preference
    High CVE-2026-40596 >= 2.11.0, < 2.28.2 2.28.2
  13. MantisBT is Vulnerable to Stored HTML Injection/XSS in Clone Issue Form
    High CVE-2026-34463 < 2.28.2 2.28.2
  14. MantisBT has Stored HTML Injection/XSS when displaying Tags in Timeline
    High · 6.1 CVE-2026-33548 >= 2.28.0, < 2.28.2 2.28.2
  15. MantisBT Vulnerable to Stored HTML Injection in Tag Delete Confirmation
    High CVE-2026-33517 >= 2.28.0, < 2.28.1 2.28.1
  16. MantisBT is vulnerable to authentication bypass through the SOAP API on MySQL
    Critical CVE-2026-30849 < 2.28.1 2.28.1
  17. MantisBT Vulnerable to Denial-of-Service (DoS) via Excessive Note Length this entry
    Medium · 6.5 CVE-2025-46556 < 2.27.2 2.27.2
  18. MantisBT vulnerable to authentication bypass for some passwords due to PHP type juggling
    High · 9.1 CVE-2025-47776 < 2.27.2 2.27.2
  19. Mantis Bug Tracker (MantisBT) allows user account takeover in the signup/reset password process
    High · 7.3 CVE-2024-34077 < 2.26.2 2.26.2
  20. MantisBT Host Header Injection vulnerability
    High · 8.3 CVE-2024-23830 < 2.26.1 2.26.1
Show more (5) Showing 20 of 25

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