CVE-2019-9792

CriticalCVSS 9.8/10Last modified Jun 17, 2026

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.

Metrics

CVSS 3.1 9.8/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-787

Affected software

Vendor	Product	Versions
Mozilla	Thunderbird	>= unspecified, < 60.6
Mozilla	Firefox ESR	>= unspecified, < 60.6
Mozilla	Firefox	>= unspecified, < 66

References

http://packetstormsecurity.com/files/153106/Spidermonkey-IonMonkey-JS_OPTIMIZED_OUT-Value-Leak.htmlExploit, Third Party Advisory, VDB Entry
https://access.redhat.com/errata/RHSA-2019:0966Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:1144Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1532599Exploit, Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/Vendor Advisory
http://packetstormsecurity.com/files/153106/Spidermonkey-IonMonkey-JS_OPTIMIZED_OUT-Value-Leak.htmlExploit, Third Party Advisory, VDB Entry
https://access.redhat.com/errata/RHSA-2019:0966Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:1144Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1532599Exploit, Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/Vendor Advisory

Timeline

Published: Apr 26, 2019
Last modified: Jun 17, 2026
NVD status: Modified

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