# CVE-2026-47156: MantisBT authentication bypass in SOAP API

Source: https://junglewise.ai/threats/cve-2026-47156-mantisbt-authentication-bypass-in-soap-api  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-09. Updated: 2026-07-15  
License: CC BY 4.0 with a link back

CVE-2026-47156 · Severity: critical · CVSS 4 · Published 2026-09-09

MantisBT, a popular open-source bug tracking system, contains a critical flaw in its SOAP API that allows unauthorized users to gain full administrator access. By exploiting this vulnerability, an attacker can read, modify, or delete all bug reports, private notes, and user data. In default installations where self-registration is enabled, even a newly registered user can impersonate any other account, including administrators, leading to total data exposure and potential service disruption.

Technologies: [MantisBT](https://junglewise.ai/threats/technologies/mantisbt), [mantisbt/mantisbt (Packagist)](https://junglewise.ai/threats/technologies/mantisbt-mantisbt). Vendors: [MantisBT](https://junglewise.ai/threats/vendors/mantisbt), [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-47156 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-47156 being exploited in the wild.

**How severe is CVE-2026-47156?** Critical severity, with a CVSS score of 4, published 9 September 2026.

**Which products and versions are affected?** MantisBT <= 2.28.3; mantisbt/mantisbt (Packagist) <= 2.28.3, ECOSYSTEM:introduced=0,fixed=2.28.4.

**Is there a fix for CVE-2026-47156?** Yes. mantisbt/mantisbt (Packagist): upgrade to 2.28.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-47156 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-47156?** Check whether you run MantisBT or mantisbt/mantisbt (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- mantisbt/mantisbt (Packagist): upgrade to 2.28.4 or later

  ```sh
  composer require mantisbt/mantisbt:^2.28.4
  ```


## Technical details

A critical authentication bypass (CWE-287/CWE-639) exists in MantisBT versions 2.28.3 and earlier within the SOAP API's mci_check_login() function. The vulnerability arises because the SOAP API allows a client to provide both a username and a cookie string, but fails to verify that the cookie actually belongs to the provided username. An attacker with a valid MANTIS_STRING_COOKIE (obtainable via default self-registration) can supply their own cookie alongside the 'administrator' username to gain full administrative privileges. This attack is reachable over the network without prior valid credentials if self-registration is enabled. The REST API and Web UI are not affected as they derive the username server-side from the session or token. A patch is available in version 2.28.4.

## Affected products

- MantisBT MantisBT <= 2.28.3

## Identifiers

- CVE-2026-47156
- GHSA-c2xg-qjqw-2v98

## Timeline

- 2026-07-15: advisory
- 2026-07-15: disclosed
- 2026-07-15: patched

## References

- [https://api.github.com/users/McCaulay](https://api.github.com/users/McCaulay)
- [https://github.com/McCaulay](https://github.com/McCaulay)
- [https://api.github.com/users/McCaulay/gists%7B/gist_id%7D](https://api.github.com/users/McCaulay/gists%7B/gist_id%7D)
- [https://api.github.com/users/McCaulay/repos](https://api.github.com/users/McCaulay/repos)
- [https://avatars.githubusercontent.com/u/31845045?v=4](https://avatars.githubusercontent.com/u/31845045?v=4)
- [https://api.github.com/users/McCaulay/events%7B/privacy%7D](https://api.github.com/users/McCaulay/events%7B/privacy%7D)

## Related threats

- [MantisBT stored XSS in print_all_bug_page_word.php](https://junglewise.ai/threats/cve-2026-62944-mantisbt-stored-xss-in-print-all-bug-page-word-php)
- [MantisBT improper input validation in REST and SOAP APIs](https://junglewise.ai/threats/cve-2026-52883-mantisbt-improper-input-validation-in-rest-and-soap-apis)
- [MantisBT authorization bypass in REST and SOAP APIs](https://junglewise.ai/threats/cve-2026-52882-mantisbt-authorization-bypass-in-rest-and-soap-apis)
- [MantisBT reflected XSS in admin/install.php](https://junglewise.ai/threats/cve-2026-52881-mantisbt-reflected-xss-in-admin-install-php)
- [MantisBT reflected XSS in admin/install.php](https://junglewise.ai/threats/cve-2026-52847-mantisbt-reflected-xss-in-admin-install-php)