CVE-2026-34754: MantisBT has an Authorization Bypass that Allows Uploading Attachments to Private Issues via REST API

medium Affects mantisbt/mantisbt. Feed 2026.10.29.1, updated 2026-10-28; published 2026-05-11; advisory modified 2026-09-10.

MantisBT has an Authorization Bypass that Allows Uploading Attachments to Private Issues via REST API

Package: mantisbt/mantisbt Composer
Affected versions: <2.28.2
Fixed in: 2.28.2
Severity: medium CVSS 4.3
Exploitation: not on CISA KEV · EPSS 0% (16.1th percentile)
Published: 2026-05-11
Source: osv.dev

References

CWE-284

NVD record mantisbt/mantisbt advisories

Am I affected?

Find out in one command. phpwarden checks your composer.lock against this advisory and 20,000+ others, ranked by real-world exploitation (CISA KEV + EPSS). Free, offline, open data.

# one-time install
pip install phpwarden

# then
phpwarden deps composer.lock

Or keep it checked automatically: GitHub Action · pre-commit hook · GitLab CI · Laravel artisan command

Install docs How findings are ranked

Related advisories

CVE-2017-7615 high MantisBT allows arbitrary password reset same package: mantisbt/mantisbt
CVE-2017-7309 medium MantisBT vulnerable to XSS through config_option parameter in adm_config_report.php same package: mantisbt/mantisbt
CVE-2019-15715 high MantisBT Remote Code Execution same package: mantisbt/mantisbt
CVE-2022-28508 medium MantisBT vulnerable to XSS via unescaped output in browser_search_plugin.php same package: mantisbt/mantisbt
CVE-2020-28413 medium MantisBT SQL Injection via mc_project_get_users function same package: mantisbt/mantisbt
CVE-2017-12062 medium MantisBT vulnerable to XSS via unsanitized filter field in manage_user_page.php same package: mantisbt/mantisbt