# CVE-2026-54395: MISP UiBeta event index reflected XSS in advanced filter popup

> Reflected XSS in MISP UiBeta event index allows attackers to execute arbitrary JavaScript in victim browsers via crafted URLs.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/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:** Not needed
- **Fix available:** No
- **Published:** 12 Jun 2026
- **Updated:** 15 Jun 2026
- **Also known as:** GHSA-53gc-pj4j-m2pq

## What is CVE-2026-54395?

CVE-2026-54395 is a medium-severity cross-site scripting vulnerability in misp, published on 12 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

MISP contains a reflected cross-site scripting vulnerability in the UiBeta event index view. The urlparams value is inserted into an inline JavaScript handler using HTML escaping inside a single-quoted JavaScript string. Because browsers HTML-decode attribute values before JavaScript parsing, a crafted searcheventinfo value can restore encoded quote characters and break out of the JavaScript string. An attacker could craft a malicious URL that, when opened by a victim using the UiBeta event index, executes arbitrary JavaScript in the victim’s browser in the context of the MISP instance. The issue is fixed by encoding the value as a JavaScript string literal with json_encode() before applying HTML escaping at the attribute layer.

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

## Which versions are affected by CVE-2026-54395?


## How do I fix CVE-2026-54395?

No fix has been published for CVE-2026-54395 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54395 being exploited?

There is no known exploitation of CVE-2026-54395 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54395 and fix it if it is affected.

What it is: CVE-2026-54395 is a medium-severity cross-site scripting vulnerability in misp, published on 12 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-54395 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-2026-54395/ (Markdown: https://insights.sbomify.com/CVE-2026-54395/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54395
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54395
- OSV: https://osv.dev/vulnerability/CVE-2026-54395

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54395/
Summaries are generated and may contain mistakes; the official description above is the record.