MantisBT: Authorization Bypass in Bugnote Editing via Issue Update API

CVE-2026-42070 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

The mc_issue_update() function in MantisBT allows users having update_bug_threshold access (UPDATER, with default settings) to edit, change view state, and modify time tracking on bugnotes belonging to other users — bypassing the default DEVELOPER (level 55) threshold required by the dedicated mc_issue_note_update() function.

Impact

  1. UPDATER can edit notes by DEVELOPER/MANAGER/ADMIN — bypassing the DEVELOPER threshold
  2. UPDATER can change private notes to public — exposing confidential internal discussion
  3. UPDATER can change public notes to private — hiding information from reporters/viewers

Patches

  • 6e58fae4f22efdc3987f903c8ba2611de17a9435

Workarounds

None

Credits

Thanks to the following security researchers for independently discovering and responsibly reporting the issue.
- Vishal Shukla
- Tristan Madani (@TristanInSec) from Talence Security

This advisory's contents was largely copied from Tristan's well-written report.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-05-11 19:39:31 UTC
Updated
2026-06-09 10:23:44 UTC
GitHub reviewed
2026-05-11 19:39:31 UTC
NVD published
2026-05-28

EPSS Score

Score Percentile
0.04% 13.59%

CVSS Scores

Base score Version Severity Vector
5.3 4.0 —
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:L)
Limited confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:L)
Limited availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.

Identifiers

Type Value
GHSA GHSA-pq86-j2c2-47f6 ↗
CVE CVE-2026-42070 ↗

CWEs

CWE id Name
CWE-863 Incorrect Authorization

Credits

  • shukla304 (finder)
  • TristanInSec (finder)
  • dregad (coordinator)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer mantisbt/mantisbt <= 2.28.1 2.28.2 —

References

cvelogic Threat Intelligence