CVE-2019-11707

KEVMozilla Firefox and Thunderbird Type Confusion Vulnerability

Description

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.

A type confusion vulnerability can occur when manipulating JavaScript objects due to issues in Array.pop. This can allow for an exploitable crash. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 60.7.1, Firefox < 67.0.3, and Thunderbird < 60.7.2.

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

PublishedJul 23, 2019

Last modifiedJun 17, 2026

Added to KEVMay 23, 2022

Remediation dueJun 13, 2022

References

bugzilla.mozilla.org/show_bug.cgi?id=1544386Issue TrackingPermissions Required
security.gentoo.org/glsa/201908-12Third Party Advisory
mozilla.org/security/advisories/mfsa2019-18/Vendor Advisory
mozilla.org/security/advisories/mfsa2019-20/Vendor Advisory
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-11707US Government Resource

0 recent articles mention this CVE

Risk assessment · High

Actively exploited. Patch immediately.

Exploitation: Confirmed in the wild (CISA KEV)
Federal remediation deadline: Overdue by 1597 days
CVSS: 8.8 HIGH
EPSS (30-day exploit probability): 38.0% · top 1% of all CVEs
Weakness: CWE-843
Attack vector: Network, remotely reachable

Recommended actions

1.Apply updates per vendor instructions.
2.Treat as emergency change: patch or isolate internet-facing instances first.
3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.

Assessment is derived automatically from the live signals above; verify against your own asset inventory.