# CVE-2026-103662: MISP Reflected XSS in Taxonomy Tag Confirmation Forms

> Reflected XSS in MISP allows attackers to execute scripts in admin browsers via crafted URLs, potentially leading to session theft or privileged actions.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **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:** 1 Oct 2026
- **Updated:** 1 Oct 2026
- **Also known as:** GHSA-p9m5-xwgx-8j69

## What is CVE-2026-103662?

CVE-2026-103662 is a medium-severity cross-site scripting vulnerability in MISP, published on 1 Oct 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 legacy taxonomy tag management confirmation forms (add tag and disable tag).

The affected forms echoed a user-supplied tag name value from the request unescaped into the rendered HTML output. An attacker who can induce a site administrator to visit a crafted URL containing a malicious tag name parameter can execute arbitrary JavaScript in the administrator's browser session.

Preconditions:

- The target must be running a MISP instance with the legacy taxonomy tag confirmation views enabled.

- The victim must be an authenticated site administrator.

- The victim must navigate to the attacker-crafted URL (e.g., via a phishing link).

Security impact:

- Execution of arbitrary client-side script in the context of the administrator's browser.

- Potential theft of session tokens, CSRF tokens, or other sensitive data accessible from the page.

- Potential for performing privileged actions on behalf of the administrator within the MISP interface.

Affected versions: <2.5.48.

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

## Which versions are affected by CVE-2026-103662?


## How do I fix CVE-2026-103662?

No fix has been published for CVE-2026-103662 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103662 being exploited?

There is no known exploitation of CVE-2026-103662 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103662 and fix it if it is affected.

What it is: CVE-2026-103662 is a medium-severity cross-site scripting vulnerability in MISP, published on 1 Oct 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-2026-103662 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-2026-103662/ (Markdown: https://insights.sbomify.com/CVE-2026-103662/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103662
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103662
- OSV: https://osv.dev/vulnerability/CVE-2026-103662

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103662/
Summaries are generated and may contain mistakes; the official description above is the record.