CVE-2019-17026

Name: CVE-2019-17026
Creator: NVD / NIST
Published: 2020-03-02T05:15:12.01+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10Actively ExploitedEPSS 46.59%

Last modified Jun 17, 2026

CVE-2019-17026 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. CISA has confirmed active exploitation in the wild. EPSS estimates a 46.59% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

46.59%

98.7th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by May 3, 2022.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 68.4.1
Mozilla	Firefox	< 72.0.1
Mozilla	Thunderbird	< 68.4.1
Canonical	Ubuntu Linux	16.04

References

http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.htmlExploit, Third Party Advisory, VDB Entry
https://bugzilla.mozilla.org/show_bug.cgi?id=1607443Issue Tracking
https://security.gentoo.org/glsa/202003-02Third Party Advisory
https://usn.ubuntu.com/4335-1/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-03/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-04/Vendor Advisory
http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.htmlExploit, Third Party Advisory, VDB Entry
https://bugzilla.mozilla.org/show_bug.cgi?id=1607443Issue Tracking
https://security.gentoo.org/glsa/202003-02Third Party Advisory
https://usn.ubuntu.com/4335-1/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-03/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-04/Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-17026US Government Resource

Timeline

Published: Mar 2, 2020
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2019-17026?

How severe is CVE-2019-17026?

CVE-2019-17026 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 46.59% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2019-17026?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-17026?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST