$ cve CVE-2019-9792 JSON

CVE-2019-9792 EXPLOIT

9.8

CRITICAL · CVSS 3.1 · EPSS 13.2% (pctl 96)

Patch early

A public exploit exists.

Description

The IonMonkey just-in-time (JIT) compiler can leak an internal JS_OPTIMIZED_OUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

Scoring

CVSS	9.8 (CRITICAL, v3.1)
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS	13.2% — more likely to be exploited than 96% of all CVEs
Weakness	CWE-787
On CISA KEV	no
Public exploit	yes
Published	2019-04-26
Last modified	2026-06-17

Affected (6)

Vendor	Product
mozilla	firefox
mozilla	thunderbird
redhat	enterprise linux
redhat	enterprise linux eus
redhat	enterprise linux server aus
redhat	enterprise linux server tus

Public exploits

Source	Title	Date
exploit-db	Spidermonkey - IonMonkey Leaks JS_OPTIMIZED_OUT Magic Value to Script	2019-05-29

References

→ the Explorer · watch your stack · NVD