CVE-2019-9801: Input Validation
First published: Tue Mar 19 2019(Updated: )
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.
Credit: security@mozilla.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Mozilla Firefox | <66 | 66 |
| <66 | 66 | |
| <60.6 | 60.6 | |
| <60.6 | 60.6 | |
| Mozilla Firefox | <66.0 | |
| Mozilla Firefox ESR | <60.6 | |
| Mozilla Thunderbird | <60.6 | |
| Microsoft Windows |
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Reference Links
- https://bugzilla.mozilla.org/show_bug.cgi?id=1527717
- https://www.mozilla.org/security/advisories/mfsa2019-07/
- https://www.mozilla.org/security/advisories/mfsa2019-08/
- https://www.mozilla.org/security/advisories/mfsa2019-11/
- https://www.mozilla.org/en-US/security/advisories/mfsa2019-11/
- https://www.mozilla.org/en-US/security/advisories/mfsa2019-07/
- https://www.mozilla.org/en-US/security/advisories/mfsa2019-08/
Peer vulnerabilities
(Found alongside the following vulnerabilities)
Frequently Asked Questions
What is CVE-2019-9801?
CVE-2019-9801 is a vulnerability in Firefox and Thunderbird that allows any registered Program ID to be accepted as an external protocol handler on Windows operating systems.
How does CVE-2019-9801 affect Mozilla Firefox?
Mozilla Firefox versions up to and including 66 are affected by CVE-2019-9801.
How does CVE-2019-9801 affect Mozilla Thunderbird?
Mozilla Thunderbird versions up to and including 60.6 are affected by CVE-2019-9801.
What is the severity of CVE-2019-9801?
CVE-2019-9801 has a severity rating of 5.3 (Medium).
How can I mitigate the vulnerability?
Update Mozilla Firefox to version 66 or later, or update Mozilla Thunderbird to version 60.6 or later to mitigate CVE-2019-9801.
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