# CVE-2026-16368: Mozilla Firefox incorrect boundary conditions in WebAssembly

Source: https://junglewise.ai/threats/cve-2026-16368-mozilla-firefox-incorrect-boundary-conditions-in-webassembly  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-21. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-16368 · Severity: info · CVSS 8.8 · Published 2026-07-21

Mozilla Firefox is a widely used web browser. A vulnerability in its WebAssembly component could allow a malicious website to execute unauthorized code or crash the browser when a user visits a specially crafted page. This could lead to the theft of sensitive information or a complete compromise of the user's computer.

Technologies: [Mozilla Firefox](https://junglewise.ai/threats/technologies/firefox), [Mozilla Firefox ESR](https://junglewise.ai/threats/technologies/firefox-esr). Vendors: [Mozilla](https://junglewise.ai/threats/vendors/mozilla).

## Quick answers

**Is CVE-2026-16368 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-16368 being exploited in the wild.

**How severe is CVE-2026-16368?** Informational severity, with a CVSS score of 8.8, published 21 July 2026.

**Which products and versions are affected?** Mozilla Firefox < 153; Mozilla Firefox ESR < 140.13.

**Is there a fix for CVE-2026-16368?** A patch was published on 2026-07-21. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-16368 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-16368?** Check whether you run Mozilla Firefox or Mozilla Firefox ESR at an affected version. 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

An incorrect boundary condition vulnerability exists in the JavaScript: WebAssembly component of Mozilla Firefox. The flaw is rooted in improper validation of array or buffer boundaries during WebAssembly execution. An attacker can exploit this by enticing a user to visit a malicious website containing specially crafted WebAssembly code. Successful exploitation could lead to memory corruption, potentially allowing for arbitrary code execution within the context of the browser process or a denial-of-service (browser crash). The vulnerability is addressed in Firefox 153 and Firefox ESR 140.13.

## Affected products

- Mozilla Firefox < 153
- Mozilla Firefox ESR < 140.13

## Timeline

- 2026-07-21: disclosed
- 2026-07-21: patched
- 2026-07-21: advisory

## References

- [https://bugzilla.mozilla.org/show_bug.cgi?id=2051015](https://bugzilla.mozilla.org/show_bug.cgi?id=2051015)
- [https://www.mozilla.org/security/advisories/mfsa2026-68/](https://www.mozilla.org/security/advisories/mfsa2026-68/)
- [https://www.mozilla.org/security/advisories/mfsa2026-70/](https://www.mozilla.org/security/advisories/mfsa2026-70/)

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