# CVE-2026-78077: Cross-site scripting in Helix Ultimate extension for Joomla

> Attackers can inject malicious scripts via unsanitized MegaMenu configuration values, leading to stored XSS in the Helix Ultimate Joomla extension.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-v6p2-jx9w-8967

## What is CVE-2026-78077?

CVE-2026-78077 is a high-severity cross-site scripting vulnerability in joomshaper.com Helix Ultimate extension for Joomla, published on 31 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Joomla Extension - joomshaper.com -  Stored Cross-Site Scripting (XSS) in MegaMenu Layout Container & Embed Inputs in Helix Ultimate < 2.2.10 - Unsanitized column and item configuration values stored within the MegaMenu layout JSON were rendered without complete contextual escaping, allowing injection of malicious HTML/JS. Stricter sanitization and tag allowlists via `InputFilter` and `htmlspecialchars` were implemented.

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

## Which versions are affected by CVE-2026-78077?


## How do I fix CVE-2026-78077?

No fix has been published for CVE-2026-78077 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78077 being exploited?

There is no known exploitation of CVE-2026-78077 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78077 and fix it if it is affected.

What it is: CVE-2026-78077 is a high-severity cross-site scripting vulnerability in joomshaper.com Helix Ultimate extension for Joomla, published on 31 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-78077 in the wild and no public exploit code.

Affected product: joomshaper.com Helix Ultimate extension for Joomla. 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-2026-78077/ (Markdown: https://insights.sbomify.com/CVE-2026-78077/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78077
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78077
- OSV: https://osv.dev/vulnerability/CVE-2026-78077

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78077/
Summaries are generated and may contain mistakes; the official description above is the record.