# CVE-2026-77992: Fabrik calc element heredoc terminator breakout in onUpdateComment endpoint

Source: https://junglewise.ai/threats/cve-2026-77992-fabrik-calc-element-heredoc-terminator-breakout-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-22. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-77992 · Severity: info · CVSS 9.8 · Published 2026-08-22

Fabrik is a Joomla extension for building custom web applications without programming knowledge. A vulnerability in versions before 4.7.2 allows attackers to execute arbitrary code through a heredoc terminator breakout in the calc element, combined with missing access controls on the onUpdateComment endpoint. This could result in complete compromise of the website and any data it manages.

## Quick answers

**Is CVE-2026-77992 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77992 being exploited in the wild.

**How severe is CVE-2026-77992?** Informational severity, with a CVSS score of 9.8, published 22 August 2026.

**Which products and versions are affected?** fabrikar.com Fabrik before 4.7.2.

**Is there a fix for CVE-2026-77992?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-77992 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-77992?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a heredoc terminator breakout in the calc element of Fabrik, paired with insufficient access controls on the onUpdateComment endpoint. The calc element processes mathematical expressions using PHP heredoc syntax, and a specially crafted payload can break out of the heredoc terminator, allowing arbitrary PHP code injection. The onUpdateComment endpoint fails to perform authorization checks, allowing unauthenticated or low-privileged attackers to trigger the vulnerable code path. No network-based authentication is required if the endpoint is accessible. A successful exploit results in remote code execution with the privileges of the web server process. Fixed in Fabrik version 4.7.2 and later.

## Affected products

- fabrikar.com Fabrik before 4.7.2

## Timeline

- 2026-08-22: disclosed

## References

- [https://www.fabrikar.com/](https://www.fabrikar.com/)