CISA KEV catalog
Confirmed active exploitation.
Listed in CISA's catalog of Known Exploited Vulnerabilities: attackers are using it in real attacks. Patch it with priority.
- Name
- Mozilla Firefox And Thunderbird Type Confusion Vulnerability
- Added to catalog
- Remediation due date (US federal)
- Required action
- Apply updates per vendor instructions.
Description
Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.
Affected products
mozilla: firefox; mozilla: thunderbird; canonical: ubuntu linux
References10
- www.mozilla.org/security/advisories/mfsa2020-03/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2020-04/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2020-03/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2020-04/ Vendor Advisory
- packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-T… ExploitThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-T… ExploitThird Party AdvisoryVDB Entry
- bugzilla.mozilla.org/show_bug.cgi?id=1607443 Issue Tracking
- security.gentoo.org/glsa/202003-02 Third Party Advisory
- usn.ubuntu.com/4335-1/ Third Party Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=1607443 Issue Tracking
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 46% percentile: 99 · as of 11 November 2026
- CWE
- CWE-843
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