Vulnerability identifier: #VU50038

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-15685

CWE-ID: CWE-94

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Thunderbird
Client/Desktop applications / Messaging software

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to improper input validation when processing plaintext phase of the IMAP STARTTLS connection setup. A remote attacker can pass protocol commands, which can be evaluated within the encrypted session.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Thunderbird: 78.0 - 78.6.1, 68.0 - 68.12.1, 60.0 - 60.9.1

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2021-05/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.