Mozilla: Disable hyperthreading on content JavaScript threads on macOS
Published Jul 23, 2019
8.1
HIGHCVSS 3.0
EPSS 1.83%
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.
Affected products
-
- Version unspecifiedStatusaffectedConstraints<67
- Version
-
- Version unspecifiedStatusaffectedConstraints<60.7
- Version
-
- Version unspecifiedStatusaffectedConstraints<60.7
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Mozilla | Firefox | n/a |
| ||||||
| Mozilla | Firefox ESR | n/a |
| ||||||
| Mozilla | Thunderbird | n/a |
|
- < 67.0
- < 60.7
- < 60.7
No data.
Red Hat Enterprise Linux 6
firefox
Not affected
Red Hat Enterprise Linux 6
thunderbird
Not affected
Red Hat Enterprise Linux 7
firefox
Not affected
Red Hat Enterprise Linux 7
thunderbird
Not affected
Red Hat Enterprise Linux 8
firefox
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 7 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 7 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 8 | firefox | Not affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
AV:N/AC:M/Au:N/C:P/I:P/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (18 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 1.83% (0.01828) | 78.09th | v5 (v2026.06.15) |
| Jun 15, 2026 | 1.83% (0.01828) | 75.97th | v5 (v2026.06.15) |
| Mar 30, 2025 | 1.02% (0.01020) | 75.21th | v4 (v2025.03.14) |
| Mar 29, 2025 | 2.10% (0.02102) | 73.43th | v4 (v2025.03.14) |
| Jul 20, 2024 | 0.67% (0.00671) | 80.02th | v3 (v2023.03.01) |
| Jul 16, 2024 | 0.67% (0.00671) | 80.00th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.47% (0.00466) | 74.74th | v3 (v2023.03.01) |
| May 27, 2023 | 0.47% (0.00466) | 71.90th | v3 (v2023.03.01) |
| May 12, 2023 | 0.34% (0.00338) | 67.07th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.28% (0.00283) | 63.60th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.02% (0.01018) | 40.69th | v2 (v2022.01.01) |
| Sep 10, 2022 | 1.02% (0.01018) | 38.88th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.02% (0.01018) | 36.86th | v2 (v2022.01.01) |
| Feb 4, 2022 | 15.35% (0.15351) | 91.59th | v2 (v2022.01.01) |
| Feb 3, 2022 | 0.82% (0.00822) | 22.20th | v1 |
| Jan 6, 2022 | 0.82% (0.00822) | 21.60th | v1 |
| Sep 1, 2021 | 0.18% (0.00184) | 3.19th | v1 |
| Apr 14, 2021 | 0.18% (0.00184) | 0.00th | v1 |
References (10)
- https://access.redhat.com/security/cve/CVE-2019-9815 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1546544 x_refsource_MISCPermissions RequiredThird Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1712624 Issue Tracking
- https://mdsattacks.com/ x_refsource_MISCThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2019-9815
- https://www.cve.org/CVERecord?id=CVE-2019-9815
- https://www.mozilla.org/en-US/security/advisories/mfsa2019-14/#CVE-2019-9815
- https://www.mozilla.org/security/advisories/mfsa2019-13/ x_refsource_MISCVendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-14/ x_refsource_MISCVendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-15/ x_refsource_MISCVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2019-9815 | Vendor Advisory | |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1546544 | x_refsource_MISCPermissions RequiredThird Party Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1712624 | Issue Tracking | |
| https://mdsattacks.com/ | x_refsource_MISCThird Party Advisory | |
| https://nvd.nist.gov/vuln/detail/CVE-2019-9815 | ||
| https://www.cve.org/CVERecord?id=CVE-2019-9815 | ||
| https://www.mozilla.org/en-US/security/advisories/mfsa2019-14/#CVE-2019-9815 | ||
| https://www.mozilla.org/security/advisories/mfsa2019-13/ | x_refsource_MISCVendor Advisory | |
| https://www.mozilla.org/security/advisories/mfsa2019-14/ | x_refsource_MISCVendor Advisory | |
| https://www.mozilla.org/security/advisories/mfsa2019-15/ | x_refsource_MISCVendor Advisory |
Change history (0)
No recorded changes yet.