CVE DATABASE / CVE-2019-17026
CVE-2019-17026
Mozilla Firefox And Thunderbird Type Confusion Vulnerability
CVSS 8.8 · HIGH
⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2021-11-03.
Federal remediation due 2022-05-03.
Required action: Apply updates per vendor instructions.
Summary
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 breakdown
| Base score | 8.8 (HIGH) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | REQUIRED |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity | HIGH |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Mozilla firefoxMozilla thunderbirdCanonical ubuntu linux
Check this CVE live
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References
- http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1607443
- https://security.gentoo.org/glsa/202003-02
- https://usn.ubuntu.com/4335-1/
- https://www.mozilla.org/security/advisories/mfsa2020-03/
- https://www.mozilla.org/security/advisories/mfsa2020-04/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-17026
Data: NIST NVD + CISA KEV. NVD last modified 2025-11-04. Always verify against the vendor advisory before acting.