# Mozilla Thunderbird (en-US) 78.11.0

Mozilla Thunderbird (en-US) 78.11.0, released May 28, 2021, fixes 2 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-78.11.0
- Platform: Windows apps
- Released: May 28, 2021
- Priority: High (Closes CVE-2021-29967, high severity)
- CVEs: 2, 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- Superseded by: [Mozilla Thunderbird (en-US) 159.0](https://patchblox.com/security/data/product/windows-app/mozilla-thunderbird-en-us.md), the latest version, which also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) |  | 78.11.0 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-29967](https://patchblox.com/security/data/cve/CVE-2021-29967.md) | High | Firefox ESR and 3 others: Mozilla developers reported memory safety bugs present in Firefox 88 and Firefox ESR 78.11. | 8.8 | 0.0137 |  |
| [CVE-2021-29964](https://patchblox.com/security/data/cve/CVE-2021-29964.md) | High | Firefox ESR and 3 others: A locally-installed hostile program could send `WM_COPYDATA` messages that Firefox would process incorrectly,… | 7.1 | 0.0082 |  |

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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