# CVE-2021-29969: Thunderbird and 1 other: If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker injected IMAP server…

CVE-2021-29969 is fixed in 7 products on 2 platforms, first by Mozilla Thunderbird (en-US) 78.12.0, released July 12, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-29969
- Priority: Routine
- CVSS: 5.9 (Important)
- EPSS: 0.0120
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 26, 2021
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2021-29969

## Description

If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker injected IMAP server responses prior to the completion of the STARTTLS handshake, then Thunderbird didn't ignore the injected data. This could have resulted in Thunderbird showing incorrect information, for example the attacker could have tricked Thunderbird to show folders that didn't exist on the IMAP server. This vulnerability affects Thunderbird < 78.12.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Mozilla Thunderbird (en-US) | 78.12.0 | [Mozilla Thunderbird (en-US) 78.12.0](https://patchblox.com/security/data/fix/windows-app/mozilla.thunderbird-78.12.0.md) | Jul 12, 2021 |
| Linux | thunderbird RHEL 8 | 0:78.12.0-3.el8_4 | [RHSA-2021:2883](https://patchblox.com/security/data/fix/linux/rhsa-2021-2883.md) | Jul 26, 2021 |
| Linux | thunderbird Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [thunderbird 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [thunderbird 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | thunderbird ol 8 | 0:78.12.0-3.0.1.el8_4 | [ELSA-2021-2883](https://patchblox.com/security/data/fix/linux/elsa-2021-2883.md) | Jul 27, 2021 |
| Linux | thunderbird-gnome-support Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [thunderbird-gnome-support 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird-gnome-support Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [thunderbird-gnome-support 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-gnome-support-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | thunderbird-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [thunderbird-mozsymbols 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird-mozsymbols Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [thunderbird-mozsymbols 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-mozsymbols-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | xul-ext-calendar-timezones Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [xul-ext-calendar-timezones 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | xul-ext-calendar-timezones Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [xul-ext-calendar-timezones 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-calendar-timezones-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | xul-ext-gdata-provider Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [xul-ext-gdata-provider 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | xul-ext-gdata-provider Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [xul-ext-gdata-provider 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-gdata-provider-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | xul-ext-lightning Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [xul-ext-lightning 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-lightning-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | xul-ext-lightning Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [xul-ext-lightning 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-lightning-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |

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