CVE-2019-17026
Mozilla Firefox And Thunderbird Type Confusion Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 May 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 46.31% probability · 99th percentile
- Public exploits
- 1 in Exploit-DB · first 13 May 2021
- CISA KEV
- Listed 3 November 2021 · due 3 May 2022
- Weakness
- CWE-843
- Affected
- mozilla/firefox · mozilla/thunderbird · canonical/ubuntu linux
- Source
- security@mozilla.org
EPSS 46.3% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2019-17026
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.