CVE-2026-34390: Mantisbt/mantisbt MantisBT Vulnerable To Privilege Escalation Vulnerability

MODERATE
Advisory Identifier: GHSA-frf7-jhp9-jxm6
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CWE-284
Published
Advisory Summary

CVE-2026-34390 is a MODERATE mantisbt vulnerable to privilege escalation vulnerability (CWE-284: Improper Access Control) affecting Mantisbt/mantisbt libraries in the Packagist ecosystem. The issue involves mantisbt vulnerable to privilege escalation from manager to administrator. Remediation is available by upgrading affected packages to version 2.28.2.

CVE-2026-34390 at a Glance

CVE Identifier CVE-2026-34390
GHSA Identifier GHSA-frf7-jhp9-jxm6
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-284: Improper Access Control
Affected Product Mantisbt/mantisbt
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-34390

To remediate this vulnerability, upgrade all affected Mantisbt/mantisbt dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mantisbt/mantisbt fixed: 2.28.2 
Upgrade mantisbt/mantisbt to 2.28.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for mantisbt/mantisbt

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-34390, inspect your project dependencies for Mantisbt/mantisbt:

inspect dependencies for mantisbt/mantisbt

Analyze the terminal output to locate any version of Mantisbt/mantisbt in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.28.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-284: Improper Access Control, where the product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. In Mantisbt/mantisbt, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Insufficient access control checks in _ProjectUsersAddCommand_ (used in *manage_proj_user_add.php* and REST API endpoint `PUT /project/{id}/users`) allows users having *manage_project_threshold* access level (*manager* by default) to grant project-level *administrator* access to any user (including themselves) in any Project they have *manager* rights in. The normal project-user add form does restrict the selectable access levels to the actor's own project role or below. However, the backend handler still accepts a forged higher access_level value and writes it. ### Impact Privilege escalation. The consequences of the privilege escalation are not as bad as it may sound, because having *administrator* access at Project level is effectively not very different from being *manager*, it does not actually give administrator privileges on the whole MantisBT instance. In particular, it does not let the upgraded user delete the Project or grant them any access to global administrative functions such as managing Users, Projects, Plugins, Custom Fields, etc. ### Patches - 69e0180f180ed5acf48a8d281a73683a7bf32461 ### Workarounds None ### Credits Thanks to the following security researchers for independently discovering and responsibly reporting the issue: - [Dracosec Research Limited](https://dracosec.tech/) (Siu Nam Tang, Chris Chan, Krecendo Hui, William Lam) - Vishal Shukla

CVE-2026-34390 Affected Mantisbt/mantisbt Versions

1 component(s)
Fixed Versions:
2.28.2
Product / Package Ecosystem Affected Versions Fixed Version
mantisbt/mantisbt
 Packagist
< 2.28.2
2.28.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mantisbt/mantisbt/security/advisories/GHSA-frf7-jhp9-jxm6
NVD — CVE-2026-34390 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34390
Security Fix Commit FIX COMMIT
https://github.com/mantisbt/mantisbt/commit/69e0180f180ed5acf48a8d281a73683a7bf32461
Mantisbt/mantisbt Source Repository REPOSITORY
https://github.com/mantisbt/mantisbt
mantisbt.org/bugs/view.php WEB
https://mantisbt.org/bugs/view.php?id=36995
mantisbt.org/bugs/view.php WEB
https://mantisbt.org/bugs/view.php?id=37002

Frequently Asked Questions

What is CVE-2026-34390?
CVE-2026-34390 is a security vulnerability in Mantisbt/mantisbt involving MantisBT Vulnerable to Privilege Escalation from Manager to Administrator under CWE-284: Improper Access Control.
Which Mantisbt/mantisbt versions are affected?
Affected versions include releases prior to 2.28.2 across affected packages: mantisbt/mantisbt.
What version fixes CVE-2026-34390?
Upgrading to 2.28.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mantisbt/mantisbt affected?
Yes, mantisbt/mantisbt is affected in releases prior to 2.28.2. Upgrade your dependency to 2.28.2 or later.
What CWE is associated with CVE-2026-34390?
CVE-2026-34390 is classified under CWE-284: Improper Access Control (The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.).
How can I check Packagist dependencies for CVE-2026-34390?
Run the dependency tree command: 'inspect dependencies for mantisbt/mantisbt'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-frf7-jhp9-jxm6",
  "modified" : "2026-06-05T14:12:12Z",
  "published" : "2026-05-11T19:32:06Z",
  "aliases" : [ "CVE-2026-34390" ],
  "summary" : "MantisBT Vulnerable to Privilege Escalation from Manager to Administrator",
  "details" : "Insufficient access control checks in _ProjectUsersAddCommand_ (used in *manage_proj_user_add.php* and REST API endpoint `PUT /project/{id}/users`) allows users having *manage_project_threshold* access level (*manager* by default) to grant project-level *administrator* access to any user (including themselves) in any Project they have *manager* rights in.\n\nThe normal project-user add form does restrict the selectable access levels to the actor's own project role or below. However, the backend handler still accepts a forged higher access_level value and writes it.\n\n### Impact\nPrivilege escalation.\n\nThe consequences of the privilege escalation are not as bad as it may sound, because having *administrator* access at Project level is effectively not very different from being *manager*, it does not actually give administrator privileges on the whole MantisBT instance. In particular, it does not let the upgraded user delete the Project or grant them any access to global administrative functions such as managing Users, Projects, Plugins, Custom Fields, etc. \n\n### Patches\n- 69e0180f180ed5acf48a8d281a73683a7bf32461\n\n### Workarounds\nNone\n\n### Credits\nThanks to the following security researchers for independently discovering and responsibly reporting the issue:\n- [Dracosec Research Limited](https://dracosec.tech/) (Siu Nam Tang, Chris Chan, Krecendo Hui, William Lam)\n- Vishal Shukla",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "mantisbt/mantisbt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.28.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.28.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/security/advisories/GHSA-frf7-jhp9-jxm6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34390"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/commit/69e0180f180ed5acf48a8d281a73683a7bf32461"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mantisbt/mantisbt"
  }, {
    "type" : "WEB",
    "url" : "https://mantisbt.org/bugs/view.php?id=36995"
  }, {
    "type" : "WEB",
    "url" : "https://mantisbt.org/bugs/view.php?id=37002"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T19:32:06Z",
    "nvd_published_at" : "2026-05-19T22:16:37Z"
  }
}