#VU53307 Protection Mechanism Failure in Mozilla Thunderbird - CVE-2021-29957

Vulnerability identifier: #VU53307

Vulnerability risk: Low

CVSSv4.0: 0.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-29957

CWE-ID: CWE-693

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 implemented security restrictions.

The vulnerability exists due to insufficient implementation of security measures. If a MIME encoded email contains an OpenPGP inline signed or encrypted message part, but also contains an additional unprotected part, Thunderbird did not indicate that only parts of the message are protected.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Thunderbird: 78.0 - 78.10.1

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2021-22/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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