CVE-2019-9815

Name: CVE-2019-9815
Creator: NVD / NIST
Published: 2019-07-23T14:15:17.03+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 1.83%

Last modified Jun 17, 2026

CVE-2019-9815 is a vulnerability of currently unknown severity. 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. EPSS estimates a 1.83% chance of exploitation in the next 30 days.

Description

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.

Metrics

EPSS Probability

1.83%

76.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-203

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 67.0
Mozilla	Firefox Esr	< 60.7
Mozilla	Thunderbird	< 60.7

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1546544Permissions Required, Third Party Advisory
https://mdsattacks.com/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2019-13/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-14/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-15/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1546544Permissions Required, Third Party Advisory
https://mdsattacks.com/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2019-13/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-14/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-15/Vendor Advisory

Timeline

Published: Jul 23, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-9815?

How severe is CVE-2019-9815?

Severity scoring for CVE-2019-9815 is pending analysis. The EPSS model estimates a 1.83% probability of exploitation in the next 30 days.

How do I fix CVE-2019-9815?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-9815?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST