# CVE-2019-17019: Firefox ESR: When Python was installed on Windows, a python file being served with the MIME type of text/plain could…

CVE-2019-17019 is fixed in Mozilla Firefox ESR (en-US) on 1 platform by Mozilla Firefox ESR (en-US) 78.0esr (version 78.0esr), released June 25, 2020. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2019-17019
- Priority: High
- CVSS: 8.8
- EPSS: 0.0105
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 8, 2020
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2019-17019

## Description

When Python was installed on Windows, a python file being served with the MIME type of text/plain could be executed by Python instead of being opened as a text file when the Open option was selected upon download. *Note: this issue only occurs on Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 72.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Mozilla Firefox ESR (en-US) | 78.0esr | [Mozilla Firefox ESR (en-US) 78.0esr](https://patchblox.com/security/data/fix/windows-app/mozilla.firefox.esr-78.0esr.md) | Jun 25, 2020 |

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Data as of 2026-11-07T18:46:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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