# CVE-2026-85227: Reflected Cross-Site Scripting in MISP Event Filtering via taggedAttributes and galaxyAttachedAttributes Parameters

> Reflected XSS in MISP allows attackers to execute JavaScript via crafted URLs, potentially accessing or modifying victim data.

- **Severity:** Medium 6.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 3 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-mj6h-p8f5-39rh

## What is CVE-2026-85227?

CVE-2026-85227 is a medium-severity cross-site scripting vulnerability in Misp-Project Misp, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

MISP contains a reflected Cross-Site Scripting (XSS) vulnerability in the event attribute filtering query builder. The taggedAttributes and galaxyAttachedAttributes URL parameters were inserted into the query-builder rules without HTML escaping before being serialized as JSON and embedded inside a <script> element.

Because JsonTool::encode() uses JSON_UNESCAPED_SLASHES, an attacker-controlled value containing a closing </script> sequence could terminate the surrounding script element and inject arbitrary HTML or JavaScript. For example, a specially crafted viewEventAttributes URL could contain malicious content in one of the affected filter parameters.

An attacker could exploit the vulnerability by convincing an authenticated MISP user to follow a crafted URL. Successful exploitation would execute attacker-controlled JavaScript in the security context of the MISP instance and with the privileges of the victim's authenticated browser session. This could allow access to information available to the victim, modification of data through authenticated requests, or other actions permitted by the victim's MISP permissions.

The vulnerability is addressed by applying HTML escaping with h() to both scalar and array values before they are inserted into the DOM.

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

## Which versions are affected by CVE-2026-85227?

It affects 1 product.


Products: Misp-Project Misp.

## How do I fix CVE-2026-85227?

No fix has been published for CVE-2026-85227 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85227 being exploited?

There is no known exploitation of CVE-2026-85227 in the wild and no public exploit code.

## Other vulnerabilities in Misp-Project Misp

- [CVE-2024-46918](https://insights.sbomify.com/CVE-2024-46918/): Missing authorization in n/a (critical 9.8)
- [CVE-2024-45509](https://insights.sbomify.com/CVE-2024-45509/): Missing authorization in n/a (critical 9.8)
- [CVE-2024-29858](https://insights.sbomify.com/CVE-2024-29858/): File upload in n/a (critical 9.8)
- [CVE-2024-29859](https://insights.sbomify.com/CVE-2024-29859/): File upload in n/a (critical 9.8)
- [CVE-2024-25674](https://insights.sbomify.com/CVE-2024-25674/): File upload in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85227 and fix it if it is affected.

What it is: CVE-2026-85227 is a medium-severity cross-site scripting vulnerability in Misp-Project Misp, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-85227 in the wild and no public exploit code.

Affected product: Misp-Project Misp. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-85227/ (Markdown: https://insights.sbomify.com/CVE-2026-85227/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85227
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85227
- OSV: https://osv.dev/vulnerability/CVE-2026-85227

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85227/
Summaries are generated and may contain mistakes; the official description above is the record.