CVE-2026-47156

MantisBT is an open source bug tracker. Versions 2.28.3 and earlier contain a critical authentication bypass in the SOAP API's mci_check_login() function. Any user knowing any valid cookie_string can authenticate as any other user (knowing their username), including the administrator, without knowing the target's password. The vulnerability is exploitable with zero prior access on default MantisBT installations because self-registration is enabled by default ($g_allow_signup = ON). A self-registered user can use their own cookie_string (readable from their browser's MANTIS_STRING_COOKIE cookie after login) to impersonate the administrator via the SOAP API. The REST API is NOT affected. The REST API's AuthMiddleware derives the username server-side from the API token or session cookie, so the username cannot be spoofed. The Web UI is NOT affected. The Web UI authenticates via PHP session cookies (PHPSESSID) and validates the MANTIS_STRING_COOKIE against the logged-in user through auth_is_cookie_valid(). The username is derived server-side from the cookie, not supplied by the client. Version 2.28.4 contains a patch. No known workarounds are available.

CVSS

No CVSS.

References

Link	Resource
https://github.com/mantisbt/mantisbt/commit/e3571c319b1721b41b0dc4b5b5203cbdcbe0c2ee
https://github.com/mantisbt/mantisbt/security/advisories/GHSA-c2xg-qjqw-2v98
https://mantisbt.org/bugs/view.php?id=37121

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-09 17:17

Updated : 2026-09-10 15:53

NVD link : CVE-2026-47156

Mitre link : CVE-2026-47156

CVE.ORG link : CVE-2026-47156

JSON object : View

Products Affected

No product.

CWE

CWE-287

Improper Authentication

CWE-639

Authorization Bypass Through User-Controlled Key

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