CVE-2026-40607: Mantisbt/mantisbt Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-f633-865q-2mhh
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CWE-79
Published
Advisory Summary

CVE-2026-40607 is a HIGH cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Mantisbt/mantisbt libraries in the Packagist ecosystem. The issue involves mantisbt is vulnerable to stored xss in saved-filter owner column. Remediation is available by upgrading affected packages to version 2.28.2.

CVE-2026-40607 at a Glance

CVE Identifier CVE-2026-40607
GHSA Identifier GHSA-f633-865q-2mhh
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Mantisbt/mantisbt
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-40607

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-2026-40607, 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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. 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

Incorrect escaping of a saved filter's owner allows an attacker to inject arbitrary HTML on systems where $g_show_user_realname = ON. ### Impact Cross-site scripting (XSS). Note that By default, only users with *Manager* access level or above can save their filters publicly ### Patches - 44f490bcf20fd491c1b8f3fc9dd041d8c2a30010 ### Workarounds - Prevent display of users' real name (set `$g_ show_user_realname = OFF;` in configuration) - Restrict ability to store filters (set $`g_stored_query_create_threshold` / $`g_stored_query_create_shared_threshold` to `NOBODY` ### Credits Thanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.

CVE-2026-40607 Affected Mantisbt/mantisbt Versions

1 component(s)
Fixed Versions:
2.28.2
Product / Package Ecosystem Affected Versions Fixed Version
mantisbt/mantisbt
 Packagist
≥ 2.1.0
< 2.28.2
2.28.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mantisbt/mantisbt/security/advisories/GHSA-f633-865q-2mhh
NVD — CVE-2026-40607 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40607
Security Fix Commit FIX COMMIT
https://github.com/mantisbt/mantisbt/commit/44f490bcf20fd491c1b8f3fc9dd041d8c2a30010
Mantisbt/mantisbt Source Repository REPOSITORY
https://github.com/mantisbt/mantisbt
mantisbt.org/bugs/view.php WEB
https://mantisbt.org/bugs/view.php?id=37015

Frequently Asked Questions

What is CVE-2026-40607?
CVE-2026-40607 is a security vulnerability in Mantisbt/mantisbt involving MantisBT is Vulnerable to Stored XSS in Saved-Filter Owner Column under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Mantisbt/mantisbt versions are affected?
Affected versions include releases prior to 2.28.2 across affected packages: mantisbt/mantisbt.
What version fixes CVE-2026-40607?
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-2026-40607?
CVE-2026-40607 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-40607?
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-f633-865q-2mhh",
  "modified" : "2026-06-08T23:20:30Z",
  "published" : "2026-05-11T19:35:05Z",
  "aliases" : [ "CVE-2026-40607" ],
  "summary" : "MantisBT is Vulnerable to Stored XSS in Saved-Filter Owner Column",
  "details" : "Incorrect escaping of a saved filter's owner allows an attacker to inject arbitrary HTML on systems where $g_show_user_realname = ON.\n\n### Impact\nCross-site scripting (XSS).\n\nNote that By default, only users with *Manager* access level or above can save their filters publicly\n\n### Patches\n- 44f490bcf20fd491c1b8f3fc9dd041d8c2a30010\n\n### Workarounds\n- Prevent display of users' real name (set `$g_ show_user_realname = OFF;` in configuration)\n- Restrict ability to store filters (set $`g_stored_query_create_threshold` / $`g_stored_query_create_shared_threshold` to `NOBODY` \n\n### Credits\nThanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "mantisbt/mantisbt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.1.0"
      }, {
        "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-f633-865q-2mhh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40607"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/commit/44f490bcf20fd491c1b8f3fc9dd041d8c2a30010"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mantisbt/mantisbt"
  }, {
    "type" : "WEB",
    "url" : "https://mantisbt.org/bugs/view.php?id=37015"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T19:35:05Z",
    "nvd_published_at" : "2026-05-22T20:16:34Z"
  }
}