Memory safety bugs present in Thunderbird ESR 140.10.1 and Thunderbird 150.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 150.0.2, Firefox ESR 140.10.2, Firefox ESR 115.35.2, Thunderbird 150.0.2, and Thunderbird 140.10.2.

End users running Thunderbird ESR 140.10.1 or Thunderbird 150.0.1, as well as those running Firefox or Firefox ESR versions prior to the patched releases, remain vulnerable. The vulnerability was fixed in Firefox 150.0.2, Firefox ESR 140.10.2, Firefox ESR 115.35.2, Thunderbird 150.0.2, and Thunderbird 140.10.2.

The CVSS score of 8.1 indicates a high severity, while the EPSS score of <1% suggests a low likelihood of exploitation in the wild. The vulnerability is not listed in CISA’s KEV catalog and no public exploits are known. The available information does not explicitly state that the flaw provides direct network access or privilege escalation; it is inferred that the vulnerability requires crafted content processed by Thunderbird to trigger memory corruption and potentially hijack control flow.