---
title: "CVE-2026-100773: Mozilla Firefox - Use After Free"
description: "Mozilla Firefox contains a use-after-free vulnerability in the Storage: IndexedDB component, letting attackers cause memory corruption or remote code execution, exploit requires no special conditions."
url: https://panop.io/threat-heartbeat/CVE-2026-100773/
---

# CVE-2026-100773 Mozilla Firefox - Use After Free

Mozilla Firefox contains a use-after-free vulnerability in the Storage: IndexedDB component, letting attackers cause memory corruption or remote code execution, exploit requires no special conditions.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.32% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-100773)

## Details

Type

Use After Free

Impact

Remote Code Execution

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Published

29 September 2026

Updated

15 October 2026

Weakness

[CWE-416](https://cwe.mitre.org/data/definitions/416.html)

## Vendor fix

Update to Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, Firefox ESR 140.17 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-100773](https://nvd.nist.gov/vuln/detail/CVE-2026-100773)
- [https://www.mozilla.org/security/advisories/mfsa2026-102/](https://www.mozilla.org/security/advisories/mfsa2026-102/)
- [https://www.mozilla.org/security/advisories/mfsa2026-103/](https://www.mozilla.org/security/advisories/mfsa2026-103/)
- [https://bugzilla.mozilla.org/show\_bug.cgi?id=2068346](https://bugzilla.mozilla.org/show_bug.cgi?id=2068346)
- [https://www.mozilla.org/security/advisories/mfsa2026-100/](https://www.mozilla.org/security/advisories/mfsa2026-100/)
- [https://www.mozilla.org/security/advisories/mfsa2026-97/](https://www.mozilla.org/security/advisories/mfsa2026-97/)
- [https://www.mozilla.org/security/advisories/mfsa2026-98/](https://www.mozilla.org/security/advisories/mfsa2026-98/)
- [https://www.mozilla.org/security/advisories/mfsa2026-99/](https://www.mozilla.org/security/advisories/mfsa2026-99/)
- [https://www.mozilla.org/security/advisories/mfsa2026-101/](https://www.mozilla.org/security/advisories/mfsa2026-101/)

[← All CVEs](https://panop.io/threat-heartbeat/)

## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

[Book a demo](https://panop.io/demo)