CVE-2017-2669

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-06-21 · updated 2026-06-17
Weakness: CWE-20

Description

Dovecot before version 2.2.29 is vulnerable to a denial of service. When 'dict' passdb and userdb were used for user authentication, the username sent by the IMAP/POP3 client was sent through var_expand() to perform %variable expansion. Sending specially crafted %variable fields could result in excessive memory usage causing the process to crash (and restart), or excessive CPU usage causing all authentications to hang.

Affected products

Debian Linux: 8.0
dovecot: from 2.2.26 through 2.2.28

References

http://www.openwall.com/lists/oss-security/2017/04/11/1
http://www.securityfocus.com/bid/97536
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2669
https://dovecot.org/pipermail/dovecot-news/2017-April/000341.html
https://github.com/dovecot/core/commit/000030feb7a30f193197f1aab8a7b04a26b42735.patch
https://www.debian.org/security/2017/dsa-3828
http://www.openwall.com/lists/oss-security/2017/04/11/1
http://www.securityfocus.com/bid/97536
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2669
https://dovecot.org/pipermail/dovecot-news/2017-April/000341.html
https://github.com/dovecot/core/commit/000030feb7a30f193197f1aab8a7b04a26b42735.patch
https://www.debian.org/security/2017/dsa-3828

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