Mozilla · Firefox Esr · CVE-2023-4578
**Name of the Vulnerable Software and Affected Versions**
Firefox versions prior to 117
Firefox ESR versions prior to 115.2
Thunderbird versions prior to 115.2
**Description**
The issue is related to the JavaScript engine SpiderMonkey in Mozilla Firefox, Firefox ESR, and Thunderbird. It involves a potential memory allocation issue when calling `JS::CheckRegExpSyntax`, which could lead to a Syntax Error. If no memory is available, a newly created Out of Memory exception could be mishandled as a Syntax Error, potentially allowing a remote attacker to cause a denial of service.
**Recommendations**
For Firefox versions prior to 117, update to version 117 or later.
For Firefox ESR versions prior to 115.2, update to version 115.2 or later.
For Thunderbird versions prior to 115.2, update to version 115.2 or later.