MantisBT has a Private Bugnote Attachment Content Leak via REST API

CVE-2026-42071 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

A missing authorization check in MantisBT's file visibility function allows any authenticated user (REPORTER+) to download attachments on private bugnotes they should not be able to access, via the REST API endpoint GET /api/rest/issues/{id}/files and SOAP API mc_issue_attachment_get endpoint.

Impact

  • REPORTER (access level 25) can view file attachments that were uploaded to private bugnotes by DEVELOPER/MANAGER/ADMIN users
  • Private bugnotes are intended for internal developer discussion; their attachments (logs, screenshots, patches) should be equally protected
  • The web UI is NOT affected — it filters through bugnote_get_all_visible_bugnotes() first

Patches

  • 029d9d203d9e4ae96b3e59d552fa7395cc1e5071

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
- Tang Cheuk Hei (@siunam321)

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

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-05-11 19:39:43 UTC
Updated
2026-06-09 10:23:53 UTC
GitHub reviewed
2026-05-11 19:39:43 UTC
NVD published
2026-05-28

EPSS Score

Score Percentile
0.05% 14.65%

CVSS Scores

Base score Version Severity Vector
7.2 4.0 —
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/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:H)
High 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-pw5x-2mf9-3xc8 ↗
CVE CVE-2026-42071 ↗

CWEs

CWE id Name
CWE-862 Missing Authorization

Credits

  • shukla304 (finder)
  • TristanInSec (finder)
  • dregad (remediation_developer)
  • siunam321 (finder)

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 >= 2.23.0, <= 2.28.1 2.28.2 —

References

cvelogic Threat Intelligence