Mozilla Firefox includes a DoS bug in its StorageManager component that allows an attacker to disrupt the browser’s operation. The flaw, which was fixed in Firefox ESR 153.4 and Firefox 157, can consume excessive storage resources and cause the application to become unresponsive. Because the description does not specify the conditions for exploitation, it is inferred that the attack likely occurs when the browser processes malicious web content that repeatedly writes to storage or forces the allocation of large storage objects.

The vulnerability affects Mozilla Firefox, specifically versions before ESR 153.4 and the regular Firefox build before 157. Users running earlier releases of either ESR or standard Firefox are potentially exposed; later releases include the fix and are not vulnerable.

The vulnerability is not listed in CISA’s KEV catalog and no EPSS score is available, suggesting limited publicly available exploitation data. The CVSS score of 6.5 indicates a medium severity. However, a DoS condition that fully incapacitates the browser still poses a significant risk to availability. The lack of an exploit score or KEV status does not negate the need for remediation. Based on the information, the most likely attack vector is via malicious web pages that trigger heavy storage usage; this inference is drawn from the nature of the StorageManager component.