CVE-2026-34754: Mantisbt/mantisbt MantisBT Has An Authorization Bypass Vulnerability

MODERATE
Advisory Identifier: GHSA-h4x5-gvx6-3rwc
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CVSS 4.3
CWE-284
Published
Advisory Summary

CVE-2026-34754 is a MODERATE (CVSS 4.3) mantisbt has an authorization bypass vulnerability (CWE-284: Improper Access Control) affecting Mantisbt/mantisbt libraries in the Packagist ecosystem. The issue involves mantisbt has an authorization bypass that allows uploading attachments to private issues via rest api. Remediation is available by upgrading affected packages to version 2.28.2.

CVE-2026-34754 at a Glance

CVE Identifier CVE-2026-34754
GHSA Identifier GHSA-h4x5-gvx6-3rwc
Severity MODERATE
CVSS v3.1 Base Score 4.3
CWE Classification CWE-284: Improper Access Control
Affected Product Mantisbt/mantisbt
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 4.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-34754

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-2026-34754, 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

### Impact MantisBT allows an authenticated user to upload attachments to private Issues they are not authorized to access. ### Patches - b262b4d2835b81394d75356dead66e52a6275206 ### Workarounds None. ### Credits Thanks to Vishal Shukla for discovering and responsibly reporting the issue.

CVE-2026-34754 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-h4x5-gvx6-3rwc
NVD — CVE-2026-34754 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34754
Security Fix Commit FIX COMMIT
https://github.com/mantisbt/mantisbt/commit/b262b4d2835b81394d75356dead66e52a6275206
Mantisbt/mantisbt Source Repository REPOSITORY
https://github.com/mantisbt/mantisbt
mantisbt.org/bugs/view.php WEB
https://mantisbt.org/bugs/view.php?id=36976

Frequently Asked Questions

What is CVE-2026-34754?
CVE-2026-34754 is a security vulnerability in Mantisbt/mantisbt involving MantisBT has an Authorization Bypass that Allows Uploading Attachments to Private Issues via REST API 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-2026-34754?
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 is the CVSS score of CVE-2026-34754?
CVE-2026-34754 has a CVSS v3.1 base score of 4.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2026-34754?
CVE-2026-34754 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-2026-34754?
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-h4x5-gvx6-3rwc",
  "modified" : "2026-06-05T14:12:34Z",
  "published" : "2026-05-11T19:33:06Z",
  "aliases" : [ "CVE-2026-34754" ],
  "summary" : "MantisBT has an Authorization Bypass that Allows Uploading Attachments to Private Issues via REST API",
  "details" : "### Impact\nMantisBT allows an authenticated user to upload attachments to private Issues they are not authorized to access.\n\n### Patches\n- b262b4d2835b81394d75356dead66e52a6275206\n\n### Workarounds\nNone.\n\n### Credits\nThanks to Vishal Shukla for discovering and responsibly reporting the issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A: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-h4x5-gvx6-3rwc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34754"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/commit/b262b4d2835b81394d75356dead66e52a6275206"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mantisbt/mantisbt"
  }, {
    "type" : "WEB",
    "url" : "https://mantisbt.org/bugs/view.php?id=36976"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T19:33:06Z",
    "nvd_published_at" : "2026-05-20T00:16:34Z"
  }
}