Hazard

Is CVE-2019-11707 being exploited?

Confirmed exploited in the wild

CISA has evidence of active exploitation. This is not theoretical risk — someone has already used it against someone.

Mozilla Firefox and Thunderbird Type Confusion Vulnerability

Mozilla · Firefox and Thunderbird

CVSS 8.8 EPSS 38% 2 public exploits Fix deadline passed 13 June 2022

What it is

Mozilla Firefox and Thunderbird contain a type confusion vulnerability that can occur when manipulating JavaScript objects due to issues in Array.pop, allowing for an exploitable crash.

Why we say that

  • 2 public exploits published
  • CISA's federal remediation deadline (2022-06-13) has passed
  • Listed in the CISA Known Exploited Vulnerabilities catalogue

Every line above comes from a named public source. Where the evidence is thin, we say so rather than inventing confidence — see methodology.

What to do

Apply updates per vendor instructions.

Public exploit code

Indexed from Exploit-DB. Presence of code raises urgency; absence does not mean safety.

What it costs when this goes wrong

This is where UK enforcement meets the vulnerability record. Where an unfixed vulnerability leads to a breach, the ICO treats it as a security failure under UK GDPR. Recent cases:

All UK cases caused by unpatched software →