# Mozilla Thunderbird (en-US) 78.2.1

Mozilla Thunderbird (en-US) 78.2.1, released August 28, 2020, fixes 3 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-78.2.1
- Platform: Windows apps
- Released: Aug 28, 2020
- Priority: High (Closes CVE-2020-15663, high severity)
- CVEs: 3, 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- Superseded by: [Mozilla Thunderbird (en-US) 159.0](https://patchblox.com/security/data/product/windows-app/mozilla-thunderbird-en-us.md), the latest version, which also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) |  | 78.2.1 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2020-15663](https://patchblox.com/security/data/cve/CVE-2020-15663.md) | High | Firefox ESR and 2 others: If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe… | 8.8 | 0.0272 |  |
| [CVE-2020-15670](https://patchblox.com/security/data/cve/CVE-2020-15670.md) | High | Firefox ESR and 2 others: Mozilla developers reported memory safety bugs present in Firefox for Android 79. | 8.8 | 0.0107 |  |
| [CVE-2020-15664](https://patchblox.com/security/data/cve/CVE-2020-15664.md) | Routine | Firefox ESR and 2 others: By holding a reference to the eval() function from an about:blank window, a malicious webpage could have… | 6.5 | 0.0139 |  |

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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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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