CVE-2026-33548: Mantisbt/mantisbt Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-73vx-49mv-v8w5
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2026-33548 is a HIGH (CVSS 6.1) 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 has stored html injection/xss when displaying tags in timeline. Remediation is available by upgrading affected packages to version 2.28.2.

CVE-2026-33548 at a Glance

CVE Identifier CVE-2026-33548
GHSA Identifier GHSA-73vx-49mv-v8w5
Severity HIGH
CVSS v3.1 Base Score 6.1
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

Security Impact

CVSS: 6.1

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

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

How to Fix CVE-2026-33548

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-2026-33548, 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

Improper escaping of tag names retrieved from History in Timeline (my_view_page.php) allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript, when displaying a tag that has been renamed or deleted. ### Impact Cross-site scripting (XSS). ### Patches f32787c14d4518476fe7f05f992dbfe6eaccd815 ### Workarounds * Edit offending History entries (using SQL) * Wrap `$this->tag_name` in a string_html_specialchars() call in IssueTagTimelineEvent::html() ### Credits MantisBT thanks Vishal Shukla for discovering and responsibly reporting the issue.

CVE-2026-33548 Affected Mantisbt/mantisbt Versions

1 component(s)
Fixed Versions:
2.28.2
Product / Package Ecosystem Affected Versions Fixed Version
mantisbt/mantisbt
 Packagist
≥ 2.28.0
< 2.28.2
All 1 versions
2.28.0
2.28.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mantisbt/mantisbt/security/advisories/GHSA-73vx-49mv-v8w5
NVD — CVE-2026-33548 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33548
Security Fix Commit FIX COMMIT
https://github.com/mantisbt/mantisbt/commit/f32787c14d4518476fe7f05f992dbfe6eaccd815
Mantisbt/mantisbt Source Repository REPOSITORY
https://github.com/mantisbt/mantisbt
mantisbt.org/bugs/view.php WEB
https://mantisbt.org/bugs/view.php?id=36973

Frequently Asked Questions

What is CVE-2026-33548?
CVE-2026-33548 is a security vulnerability in Mantisbt/mantisbt involving MantisBT has Stored HTML Injection/XSS when displaying Tags in Timeline 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-2026-33548?
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-2026-33548?
CVE-2026-33548 has a CVSS v3.1 base score of 6.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-33548?
CVE-2026-33548 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-2026-33548?
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-73vx-49mv-v8w5",
  "modified" : "2026-03-25T20:09:09Z",
  "published" : "2026-03-25T20:09:09Z",
  "aliases" : [ "CVE-2026-33548" ],
  "summary" : "MantisBT has Stored HTML Injection/XSS when displaying Tags in Timeline",
  "details" : "Improper escaping of tag names retrieved from History in Timeline (my_view_page.php) allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript, when displaying a tag that has been renamed or deleted.\n\n### Impact\nCross-site scripting (XSS).\n\n### Patches\nf32787c14d4518476fe7f05f992dbfe6eaccd815\n\n### Workarounds\n* Edit offending History entries (using SQL)\n* Wrap `$this->tag_name` in a string_html_specialchars() call in IssueTagTimelineEvent::html()\n\n### Credits\nMantisBT thanks Vishal Shukla for discovering and responsibly reporting the issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "mantisbt/mantisbt"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.28.0"
      }, {
        "fixed" : "2.28.2"
      } ]
    } ],
    "versions" : [ "2.28.0" ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/security/advisories/GHSA-73vx-49mv-v8w5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33548"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mantisbt/mantisbt/commit/f32787c14d4518476fe7f05f992dbfe6eaccd815"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mantisbt/mantisbt"
  }, {
    "type" : "WEB",
    "url" : "https://mantisbt.org/bugs/view.php?id=36973"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-25T20:09:09Z",
    "nvd_published_at" : "2026-03-23T20:16:27Z"
  }
}