8.8
High
Exploited
CVE-2019-17026 Mozilla Firefox And Thunderbird Type Confusion Vulnerability
Active exploitation observed
· CISA KEV catalogue
Required action
Apply updates per vendor instructions.
Ransomware campaigns
Not observed so far
Weakness
CWE-843
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 and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Firefox ESR 68.4 | earliest → < 68.4.1 | 68.4.1 |
| Thunderbird 68.4 | earliest → < 68.4.1 | 68.4.1 |
| Firefox 72.0 | earliest → < 72.0.1 | 72.0.1 |
References
- www.mozilla.org www.mozilla.org
- www.mozilla.org www.mozilla.org
- bugzilla.mozilla.org bugzilla.mozilla.org
- GLSA-202003-02 security.gentoo.org
- USN-4335-1 usn.ubuntu.com
- packetstormsecurity.com packetstormsecurity.com
Timeline
- Published
- Added to the KEV catalogue
- Last modified
Other CVEs of Firefox ESR
The 833 CVEs of Firefox ESR →
CVE-2026-5734
Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1
8.1
High
CVE-2026-5732
Incorrect boundary conditions, integer overflow in the Graphics: Text component
8.8
High
CVE-2026-5731
Memory safety bugs present in Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and…
9.8
Critical
CVE-2026-2447
Heap buffer overflow in libvpx
8.8
High