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
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