# CVE-2026-78000: Joomla Extension - j2commerce.com - Open redirect in cart controller in J2Store 1.0.0-3.3.20, 4.0.0-4.0.20, 4.1.0-4.1.5

> Attackers can redirect users to malicious sites via unvalidated base64 URLs in J2Store, enabling phishing attacks without authentication.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/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:** 3 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-3p2h-qrvh-pqvm

## What is CVE-2026-78000?

CVE-2026-78000 is a medium-severity vulnerability in j2commerce.com J2Store extension for Joomla, published on 3 Sep 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

Joomla Extension - j2commerce.com - Reflected XSS via `filter_tag`, `pricefrom` and `priceto` in J2Store 1.0.0-3.3.21, 4.0.0-4.0.21, 4.1.0-4.1.6 - Four task handlers accepted a base64-encoded URL from user input and redirected to it without validating the destination host, enabling phishing using the shop's trusted domain. No authentication required.

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

## Which versions are affected by CVE-2026-78000?


## How do I fix CVE-2026-78000?

No fix has been published for CVE-2026-78000 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78000 being exploited?

There is no known exploitation of CVE-2026-78000 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78000 and fix it if it is affected.

What it is: CVE-2026-78000 is a medium-severity vulnerability in j2commerce.com J2Store extension for Joomla, published on 3 Sep 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-2026-78000 in the wild and no public exploit code.

Affected product: j2commerce.com J2Store 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-2026-78000/ (Markdown: https://insights.sbomify.com/CVE-2026-78000/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78000
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78000
- OSV: https://osv.dev/vulnerability/CVE-2026-78000

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78000/
Summaries are generated and may contain mistakes; the official description above is the record.