ACTIVELY EXPLOITED

CVE-2019-11707: Mozilla Firefox and Thunderbird Type Confusion Vulnerability

Facts
VendorMozilla
ProductFirefox and Thunderbird
Actively exploitedYes
Added to CISA KEV23 May 2022
CISA federal deadline13 Jun 2022
Weakness (CWE)CWE-843

Required action (CISA's text)

Apply updates per vendor instructions.

Description (NVD)

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.

SOURCES

Other Mozilla flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.