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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-12100
• https://dovecot.org/security
• https://lists.debian.org/debian-lts-announce/2020/08/msg00024.html
• https://lists.fedoraproject.org/archives/list/[email protected]/message/4AAX2MJEULPVSRZOBX3PNPFSYP4FM4TT/
• https://lists.fedoraproject.org/archives/list/[email protected]/message/EYZU6CHA3VMYYAUCMHSCCQKJEVEIKPQ2/
• https://lists.fedoraproject.org/archives/list/[email protected]/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
• 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