Vulnerability identifier: #VU54285

Vulnerability risk: Low

CVSSv3.1: 2.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-29157

CWE-ID: CWE-22

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Dovecot
Server applications / Mail servers

Vendor: Dovecot

Description

The vulnerability allows a local user to perform directory traversal attacks.

The vulnerability exists due to validation of kid and azp fields in JWT tokens. A local user to ability to control a JWT token location can login as any MTA user and access their emails.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Dovecot: 2.3.11 - 2.3.14

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External links
http://dovecot.org/pipermail/dovecot-news/2021-June/000461.html

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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