Mozilla: Windows programs that are not 'URL Handlers' are exposed to web content
Published Apr 26, 2019
6.1
MEDIUMCVSS 3.0
EPSS 1.31%
Description
Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a matching URL on Windows operating systems. This should only happen if the program has specifically registered itself as a "URL Handler" in the Windows registry. *Note: This issue only affects Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.
Affected products
-
- Version unspecifiedStatusaffectedConstraints<66
- Version
-
- Version unspecifiedStatusaffectedConstraints<60.6
- Version
-
- Version unspecifiedStatusaffectedConstraints<60.6
- 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 |
|
- < 66.0
- < 60.6
- < 60.6
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
| 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 |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 6 and 7.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
AV:N/AC:L/Au:N/C:N/I:P/A:N
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 (14 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 1.31% (0.01310) | 69.63th | v5 (v2026.06.15) |
| Jun 15, 2026 | 1.31% (0.01310) | 66.81th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.39% (0.00390) | 58.03th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.21% (0.00209) | 59.74th | v3 (v2023.03.01) |
| Apr 19, 2024 | 0.21% (0.00209) | 58.55th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.13% (0.00128) | 45.81th | 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 | 7.18% (0.07176) | 80.33th | v2 (v2022.01.01) |
| Feb 3, 2022 | 35.03% (0.35026) | 97.90th | v1 |
| Jan 6, 2022 | 35.03% (0.35026) | 97.88th | v1 |
| Sep 1, 2021 | 10.73% (0.10726) | 95.25th | v1 |
| Apr 14, 2021 | 10.73% (0.10726) | 0.00th | v1 |
References (9)
- https://access.redhat.com/security/cve/CVE-2019-9801 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1527717 x_refsource_MISCIssue TrackingPermissions RequiredVendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1690682 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2019-9801
- https://www.cve.org/CVERecord?id=CVE-2019-9801
- https://www.mozilla.org/en-US/security/advisories/mfsa2019-08/#CVE-2019-9801
- https://www.mozilla.org/security/advisories/mfsa2019-07/ x_refsource_MISCVendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-08/ x_refsource_MISCVendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-11/ x_refsource_MISCVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2019-9801 | Vendor Advisory | |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1527717 | x_refsource_MISCIssue TrackingPermissions RequiredVendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1690682 | Issue Tracking | |
| https://nvd.nist.gov/vuln/detail/CVE-2019-9801 | ||
| https://www.cve.org/CVERecord?id=CVE-2019-9801 | ||
| https://www.mozilla.org/en-US/security/advisories/mfsa2019-08/#CVE-2019-9801 | ||
| https://www.mozilla.org/security/advisories/mfsa2019-07/ | x_refsource_MISCVendor Advisory | |
| https://www.mozilla.org/security/advisories/mfsa2019-08/ | x_refsource_MISCVendor Advisory | |
| https://www.mozilla.org/security/advisories/mfsa2019-11/ | x_refsource_MISCVendor Advisory |
Change history (0)
No recorded changes yet.