# CVE-2026-53693: MISP BSimVis stored cross-site scripting in tag and cluster rendering paths via unescaped tag metadata and UI labels

> Attackers can inject malicious scripts via tag metadata in MISP BSimVis, leading to arbitrary JavaScript execution in victim browsers.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jun 2026
- **Updated:** 10 Jun 2026
- **Also known as:** GHSA-m277-g9rj-mm6h

## What is CVE-2026-53693?

CVE-2026-53693 is a medium-severity cross-site scripting vulnerability in misp bsimvis, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A stored cross-site scripting vulnerability existed in MISP BSimVis tag rendering code. Several client-side rendering paths interpolated tag names, collection names, entity identifiers, cluster names, and tag metadata directly into HTML, HTML attributes, inline JavaScript event handlers, and CSS style values without context-appropriate escaping. The patch adds shared escaping helpers for HTML, attributes, JavaScript strings, and CSS color validation, then applies them across tag badges, tooltips, context menus, cluster cards, autocomplete suggestions, and dynamically inserted tag cards.

An attacker able to create or influence stored tag or metadata values could inject a crafted payload that is later rendered in another user’s browser. Successful exploitation could execute arbitrary JavaScript in the victim’s session when they view affected BSimVis pages, potentially allowing the attacker to perform actions as the victim, read data available to the victim, or alter displayed application content.

This issue affects MISP bsimvis: through v0.2.0.

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

## Which versions are affected by CVE-2026-53693?


## How do I fix CVE-2026-53693?

No fix has been published for CVE-2026-53693 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53693 being exploited?

There is no known exploitation of CVE-2026-53693 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53693 and fix it if it is affected.

What it is: CVE-2026-53693 is a medium-severity cross-site scripting vulnerability in misp bsimvis, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53693 in the wild and no public exploit code.

Affected product: misp bsimvis. 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-2026-53693/ (Markdown: https://insights.sbomify.com/CVE-2026-53693/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53693
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53693
- OSV: https://osv.dev/vulnerability/CVE-2026-53693

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-53693/
Summaries are generated and may contain mistakes; the official description above is the record.