The flaw in the Security: Process Sandboxing component permits an attacker to read protected data that should remain confined within the sandbox and to escape the sandbox, effectively elevating privileges inside the Firefox process. This dual capability exposes confidential information and enables the attacker to perform actions that require higher privileges, thereby compromising both confidentiality and integrity.

Mozilla Firefox browsers earlier than version 158 and the ESR branch before release 153.5 are vulnerable. All versions of Firefox that include the patch released in these versions are considered unaffected.

The CVSS score is not provided and the EPSS score is unavailable, so the explicit probability of exploitation cannot be calculated. Because the vulnerability can lead to privilege escalation, its potential impact is high. No public exploits are linked to this flaw, and it is not listed in the CISA Known Exploited Vulnerabilities catalog, but the severity warrants urgent attention until the patch is applied.