# Mozilla Thunderbird (en-US) 78.1.0

Mozilla Thunderbird (en-US) 78.1.0, released July 29, 2020, fixes 8 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-78.1.0
- Platform: Windows apps
- Released: Jul 29, 2020
- Priority: High (Closes CVE-2020-15659, high severity)
- CVEs: 8, 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- Superseded by: [Mozilla Thunderbird (en-US) 159.0](https://patchblox.com/security/data/product/windows-app/mozilla-thunderbird-en-us.md), the latest version, which also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) |  | 78.1.0 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2020-15659](https://patchblox.com/security/data/cve/CVE-2020-15659.md) | High | Firefox ESR and 2 others: Mozilla developers and community members reported memory safety bugs present in Firefox 78 and Firefox… | 8.8 | 0.0239 |  |
| [CVE-2020-15656](https://patchblox.com/security/data/cve/CVE-2020-15656.md) | High | Firefox ESR and 2 others: JIT optimizations involving the Javascript arguments object could confuse later optimizations. | 8.8 | 0.0152 |  |
| [CVE-2020-15657](https://patchblox.com/security/data/cve/CVE-2020-15657.md) | High | Firefox ESR and 2 others: Firefox could be made to load attacker-supplied DLL files from the installation directory. | 7.8 | 0.0035 |  |
| [CVE-2020-15655](https://patchblox.com/security/data/cve/CVE-2020-15655.md) | Routine | Firefox ESR and 2 others: A redirected HTTP request which is observed or modified through a web extension could bypass existing… | 6.5 | 0.0152 |  |
| [CVE-2020-15654](https://patchblox.com/security/data/cve/CVE-2020-15654.md) | Routine | Firefox ESR and 2 others: When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user… | 6.5 | 0.0142 |  |
| [CVE-2020-15653](https://patchblox.com/security/data/cve/CVE-2020-15653.md) | Routine | Firefox ESR and 2 others: An iframe sandbox element with the allow-popups flag could be bypassed when using noopener links. | 6.5 | 0.0140 |  |
| [CVE-2020-15658](https://patchblox.com/security/data/cve/CVE-2020-15658.md) | Routine | Firefox ESR and 2 others: The code for downloading files did not properly take care of special characters, which led to an attacker… | 6.5 | 0.0139 |  |
| [CVE-2020-15652](https://patchblox.com/security/data/cve/CVE-2020-15652.md) | Routine | Firefox ESR and 2 others: By observing the stack trace for JavaScript errors in web workers, it was possible to leak the result… | 6.5 | 0.0126 |  |

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Data as of 2026-11-10T13:56:55Z 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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