Vulnerability identifier: #VU17703

Vulnerability risk: Low

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-18509

CWE-ID: CWE-451

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 conduct spoofing attack.

The vulnerability exists due to a flaw during verification of certain S/MIME signatures causes emails can be shown in Thunderbird as having a valid digital signature, even if the shown message contents aren't covered by the signature. A remote attacker can reuse a valid S/MIME signature to craft an email message with arbitrary content.

Mitigation
Update to version 60.5.1.

Vulnerable software versions

Mozilla Thunderbird: 60.0 - 60.5

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2019-06/

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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.