Mozilla released memory safety bugs in Firefox 151 and Thunderbird 151 that caused memory corruption. The bugs exhibit the potential to be exploited for arbitrary code execution. The weakness is categorized as CWE‑119, which affects buffer handling and can lead to arbitrary code execution when triggered.

The affected products are Mozilla Firefox and Mozilla Thunderbird. Versions up to and including 151 are vulnerable; the vulnerability was fixed in Firefox 152 and Thunderbird 152.

The CVSS score of 8.1 indicates a high severity risk. The EPSS score is less than 1 %, suggesting that exploitation of this vulnerability is currently unlikely but not impossible. The vulnerability is not listed in the CISA KEV catalog. The attack vector is not explicitly stated in the advisory, but based on the description it is inferred that the exploit would require the affected application to be executed, potentially with user interaction or via a malicious webpage or email attachment. No public proof‑of‑concept is disclosed, so the likelihood remains low, yet the high impact warrants prompt remediation.