Vulnerability in Apple macOS

CVE-2019-9815

If hyperthreading is not disabled, a timing attack vulnerability exists, similar to previous Spectre attacks. Apple has shipped macOS 10.14.5 with an option to disable hyperthreading in applications running untrusted code in a thread through a new sysctl. Firefox now makes use of it on the main thread and any worker threads. *Note: users need to update to macOS 10.14.5 in order to take advantage of this change.*. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

EPSS: 0.018 (76.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2019-9815?
CVE-2019-9815 is a high-severity vulnerability in Apple macOS, classified under Observable Discrepancy. CVSS score: 8.1/10. Published 2019-07-23.
How severe is CVE-2019-9815?
High severity. CVSS v3 base score is 8.1 out of 10.