MantisBT: SOAP API Authentication Bypass with Privilege Escalation to Administrator (CVE-2026-47156) | HOL Guard CVE

Critical · CVSS 9.3CVE-2026-47156GHSA-C2XG-QJQW-2V98

MantisBT: SOAP API Authentication Bypass with Privilege Escalation to Administrator

Answer in brief

CVE-2026-47156 records a Critical severity (CVSS 9.3) vulnerability in MantisBT: SOAP API Authentication Bypass with Privilege Escalation to Administrator. The current sources do not mark it as known exploited. The current feed maps mantisbt/mantisbt (composer), mantisbt/mantisbt (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 9, 2026Updated Sep 10, 2026Source checked Sep 17, 2026First seen by HOL Jul 15, 2026Material review Sep 10, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.3
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps mantisbt/mantisbt (composer), mantisbt/mantisbt (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
mantisbt/mantisbtcomposer	<=2.28.3	2.28.4
mantisbt/mantisbtgeneric	< 2.28.4	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for mantisbt/mantisbt, mantisbt/mantisbt.
Review the reported fix. Update mantisbt/mantisbt to 2.28.4 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 15, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.