# CVE-2026-95659: MISP Reflected XSS via Unvalidated Object Type in AnalystData Overmind Thread

> Authenticated attackers can inject JavaScript via crafted URLs in MISP, potentially stealing session data or performing actions on behalf of victims.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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:** No
- **Published:** 22 Sep 2026
- **Updated:** 22 Sep 2026
- **Also known as:** GHSA-296v-9jwc-w27h

## What is CVE-2026-95659?

CVE-2026-95659 is a medium-severity cross-site scripting vulnerability in MISP, published on 22 Sep 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

MISP contains a reflected cross-site scripting (XSS) vulnerability in the AnalystDataController::viewForObject action. The method accepted a parent object type parameter from the URL without validation and passed it to the Overmind-themed AnalystData thread view element, where it was interpolated into two translated strings and rendered into the HTML response without output encoding. An authenticated attacker who can induce a victim to navigate to a crafted URL can inject arbitrary JavaScript that executes in the victim's browser within the MISP application context. This may allow the attacker to read session data, manipulate the page, or perform actions on behalf of the victim. 

The vulnerability requires the victim to be authenticated to MISP and to actively visit the attacker-supplied URL. The affected component is the AnalystData controller and the Overmind theme's AnalystData thread element.

Version affected: <2.5.47

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-20 (Improper Input Validation), CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-95659?


## How do I fix CVE-2026-95659?

No fix has been published for CVE-2026-95659 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-95659 being exploited?

There is no known exploitation of CVE-2026-95659 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-95659 and fix it if it is affected.

What it is: CVE-2026-95659 is a medium-severity cross-site scripting vulnerability in MISP, published on 22 Sep 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-2026-95659 in the wild and no public exploit code.

Affected product: 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-2026-95659/ (Markdown: https://insights.sbomify.com/CVE-2026-95659/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-95659
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-95659
- OSV: https://osv.dev/vulnerability/CVE-2026-95659

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-95659/
Summaries are generated and may contain mistakes; the official description above is the record.