# Mozilla Thunderbird (en-US) 78.4.0

Mozilla Thunderbird (en-US) 78.4.0, released October 19, 2020, fixes 5 CVEs in Mozilla Thunderbird (en-US). None of them is reported as exploited. Patch Radar priority: High. The latest Mozilla Thunderbird (en-US) is 159.0, which also fixes every one of these CVEs.

- Web page: https://patchblox.com/security/fix/windows-app/mozilla.thunderbird-78.4.0
- Platform: Windows apps
- Released: Oct 19, 2020
- Priority: High (Closes CVE-2020-15683, high severity)
- CVEs: 5, exploited: 0, on CISA KEV: 0
- Superseded by: [Mozilla Thunderbird (en-US) 159.0](https://patchblox.com/security/data/product/windows-app/mozilla-thunderbird-en-us.md), the latest version, which also fixes every CVE listed here

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Mozilla Thunderbird (en-US)](https://patchblox.com/security/data/product/windows-app/mozilla-thunderbird-en-us.md) |  | 78.4.0 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2020-15683](https://patchblox.com/security/data/cve/CVE-2020-15683.md) | High | Firefox ESR and 2 others: Mozilla developers and community members reported memory safety bugs present in Firefox 81 and Firefox… | 9.8 | 0.0267 |  |
| [CVE-2020-15673](https://patchblox.com/security/data/cve/CVE-2020-15673.md) | High | Firefox ESR and 2 others: Mozilla developers reported memory safety bugs present in Firefox 80 and Firefox ESR 78.2. | 8.8 | 0.0196 |  |
| [CVE-2020-15678](https://patchblox.com/security/data/cve/CVE-2020-15678.md) | High | Firefox ESR and 2 others: When recursing through graphical layers while scrolling, an iterator may have become invalid, resulting… | 8.8 | 0.0188 |  |
| [CVE-2020-15677](https://patchblox.com/security/data/cve/CVE-2020-15677.md) | Routine | Firefox ESR and 2 others: By exploiting an Open Redirect vulnerability on a website, an attacker could have spoofed the site displayed… | 6.1 | 0.0166 |  |
| [CVE-2020-15676](https://patchblox.com/security/data/cve/CVE-2020-15676.md) | Routine | Firefox ESR and 2 others: Firefox sometimes ran the onload handler for SVG elements that the DOM sanitizer decided to remove, resulting… | 6.1 | 0.0159 |  |

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Data as of 2026-11-10T07:50:38Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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