#VU52003 Input validation error in Mozilla Thunderbird - CVE-2021-23993

Vulnerability identifier: #VU52003

Vulnerability risk: Medium

CVSSv4.0: 1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-23993

CWE-ID: CWE-20

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 disable sending of encrypted messages.

The vulnerability exists due to insufficient validation of imported OpenPGP keys. A remote attacker can force the victim to import a specially crafted OpenPGO key with a subkey that has an invalid self signature and prevent users from sending encrypted messages to a correspondent.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Thunderbird: 60.0 - 68.12.1, 78.0 - 78.9.0

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2021-13/

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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.