# CVE-2026-33517: MantisBT Vulnerable to Stored HTML Injection in Tag Delete Confirmation

> Attackers can inject HTML and execute JavaScript via tag names in MantisBT, potentially leading to account takeover if CSP allows.

- **Severity:** High 8.6 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Mar 2026
- **Updated:** 24 Mar 2026
- **Also known as:** GHSA-fh48-f69w-7vmp

## What is CVE-2026-33517?

CVE-2026-33517 is a high-severity cross-site scripting vulnerability in Mantisbt Mantisbt, published on 23 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Mantis Bug Tracker (MantisBT) is an open source issue tracker. In version 2.28.0, when deleting a Tag (tag_delete.php), improper escaping of its name when displaying the confirmation message allows an attacker to inject HTML and, if CSP settings permit, achieve execution of arbitrary JavaScript. Version 2.28.1 fixes the issue. Workarounds include reverting commit d6890320752ecf37bd74d11fe14fe7dc12335be9 and/or manually editing language files to remove the sprintf placeholder `%1$s` from `$s_tag_delete_message` string.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-33517?

2 open source packages ship an affected version, including mantisbt/mantisbt. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mantisbt/mantisbt` | Packagist | From 2.28.0 | 2.28.1 |
| `mantisbt/mantisbt` | Packagist | From 2.28.0 | 2.28.1 |

Products: Mantisbt Mantisbt.

## How do I fix CVE-2026-33517?

Upgrade mantisbt/mantisbt to 2.28.1 or later.

## Is CVE-2026-33517 being exploited?

There is no known exploitation of CVE-2026-33517 in the wild and no public exploit code.

## Other vulnerabilities in Mantisbt Mantisbt

- [CVE-2019-15074](https://insights.sbomify.com/CVE-2019-15074/): MantisBT allows cross-site scripting (XSS) via crafted filename (critical 9.6)
- [CVE-2026-30849](https://insights.sbomify.com/CVE-2026-30849/): MantisBT SOAP API has an authentication bypass vulnerability on MySQL (critical 9.3)
- [CVE-2025-47776](https://insights.sbomify.com/CVE-2025-47776/): MantisBT: Authentication bypass for some passwords due to PHP type juggling (high 8.8)
- [CVE-2017-7615](https://insights.sbomify.com/CVE-2017-7615/): MantisBT allows arbitrary password reset (high 8.8)
- [CVE-2026-33548](https://insights.sbomify.com/CVE-2026-33548/): MantisBT has Stored HTML Injection / XSS when displaying Tags in Timeline (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33517 and fix it if it is affected.

What it is: CVE-2026-33517 is a high-severity cross-site scripting vulnerability in Mantisbt Mantisbt, published on 23 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-33517 in the wild and no public exploit code.

Affected packages and fixed versions:
- mantisbt/mantisbt (Packagist): affected from 2.28.0; fixed in 2.28.1
- mantisbt/mantisbt (Packagist): affected from 2.28.0; fixed in 2.28.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-33517/ (Markdown: https://insights.sbomify.com/CVE-2026-33517/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33517
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33517
- OSV: https://osv.dev/vulnerability/CVE-2026-33517

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33517/
Summaries are generated and may contain mistakes; the official description above is the record.