# CVE-2026-77990: Missing authorization in JEM - Joomla Event Manager extension for Joomla

> Any logged-in user can read attendee lists for events they do not manage, exposing personal data. Site administrators should upgrade the extension.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/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:** 27 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-839q-fphm-4fh3

## What is CVE-2026-77990?

CVE-2026-77990 is a medium-severity missing authorization vulnerability in joomlaeventmanager.net JEM - Joomla Event Manager extension for Joomla, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Joomla Extension - joomlaeventmanager.net - Attendee lists readable by any logged-in user in Joomla Event Manager < 5.0.1 - A non-manager can therefore read attendee names, usernames, registration dates and statuses for events they do not manage, including lists belonging to unpublished events.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-77990?


## How do I fix CVE-2026-77990?

No fix has been published for CVE-2026-77990 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77990 being exploited?

There is no known exploitation of CVE-2026-77990 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77990 and fix it if it is affected.

What it is: CVE-2026-77990 is a medium-severity missing authorization vulnerability in joomlaeventmanager.net JEM - Joomla Event Manager extension for Joomla, published on 27 Aug 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-2026-77990 in the wild and no public exploit code.

Affected product: joomlaeventmanager.net JEM - Joomla Event Manager 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-2026-77990/ (Markdown: https://insights.sbomify.com/CVE-2026-77990/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77990
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77990
- OSV: https://osv.dev/vulnerability/CVE-2026-77990

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-77990/
Summaries are generated and may contain mistakes; the official description above is the record.