What’s Vulnerable › Vulnerabilities

CVE-2020-12100

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-08-12 · updated 2026-06-17
• Weakness: CWE-674

Description

In Dovecot before 2.3.11.3, uncontrolled recursion in submission, lmtp, and lda allows remote attackers to cause a denial of service (resource consumption) via a crafted e-mail message with deeply nested MIME parts.

Affected products

• Canonical Ubuntu Linux: 14.04, 16.04, 18.04, 20.04
• Debian Linux: 9.0, 10.0
• dovecot: before 2.3.11.3 — fixed in 2.3.11.3
• Fedoraproject Fedora: 31, 32, 33

How to fix

Upgrade to a fixed version: dovecot 2.3.11.3. Check the vendor advisory for mitigations.

References

• http://seclists.org/fulldisclosure/2021/Jan/18
• http://www.openwall.com/lists/oss-security/2020/08/12/1
• http://www.openwall.com/lists/oss-security/2021/01/04/3
• https://dovecot.org/security
• https://lists.debian.org/debian-lts-announce/2020/08/msg00024.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4AAX2MJEULPVSRZOBX3PNPFSYP4FM4TT/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EYZU6CHA3VMYYAUCMHSCCQKJEVEIKPQ2/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XKKAL3OMG76ZZ7CIEMQP2K6KCTD2RAKE/
• https://security.gentoo.org/glsa/202009-02
• https://usn.ubuntu.com/4456-1/
• https://usn.ubuntu.com/4456-2/
• https://www.debian.org/security/2020/dsa-4745

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