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Fencer Vulns
high 8.1

CVE-2019-9815 json

If hyperthreading is not disabled, a timing attack vulnerability exists, similar to previous Spectre attacks.

published 2019-07-23 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-19177

cvss
8.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

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.

Patch / fix

  • Mozilla Thunderbird 60.7
  • Mozilla Firefox 67
  • Mozilla Firefox ESR 60.7
  • MozillaThunderbird SLE Workstation Extension 15 SP1, SLE Workstation Extension 15 60.7.0-3.33.2
  • MozillaFirefox SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 60.7.0-3.40.6
  • MozillaFirefox SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES for SAP 12 SP2 +13 more 60.7.0-109.72.1

suse advisories SUSE-SU-2019:1458-1SUSE-SU-2019:1405-1SUSE-SU-2019:1388-1

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2
  • MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
  • MozillaThunderbird Package Hub 12 60.7.2-85.1
  • MozillaFirefox openSUSE Leap 15.0 60.7.0-lp150.3.54.5

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1openSUSE-SU-2024:10601-1openSUSE-SU-2019:1664-1openSUSE-SU-2019:1534-1

  • firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +12 more 60.7.0-r0

alpine advisories ALPINE-CVE-2019-9815

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-9815 updated cvss 7.5

Mozilla: Disable hyperthreading on content JavaScript threads on macOS

  • Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, thunderbird Red Hat Enterprise Linux 8 firefox
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.83% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 8.1 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Mozilla Thunderbird
  • Mozilla Firefox
  • Mozilla Firefox ESR

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.