CVE-2021-20247

A flaw was found in mbsync before v1.3.5 and v1.4.1. Validations of the mailbox names returned by IMAP LIST/LSUB do not occur allowing a malicious or compromised server to use specially crafted mailbox names containing '..' path components to access data outside the designated mailbox on the opposite end of the synchronization channel. The highest threat from this vulnerability is to data confidentiality and integrity.

• CWE-20
• CWE-22

• https://bugzilla.redhat.com/show_bug.cgi?id=1928963Issue Tracking, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2022/07/msg00001.htmlMailing List, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CAXQLCK35QGRCRENRTGKJO4VVZGUXUJJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GVDEBZQJMWDW5JFK4NTHH6DAFNAZTESW/
• https://security.gentoo.org/glsa/202208-15Third Party Advisory
• https://www.openwall.com/lists/oss-security/2021/02/22/1Exploit, Mailing List, Third Party Advisory
• https://bugzilla.redhat.com/show_bug.cgi?id=1928963Issue Tracking, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2022/07/msg00001.htmlMailing List, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CAXQLCK35QGRCRENRTGKJO4VVZGUXUJJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GVDEBZQJMWDW5JFK4NTHH6DAFNAZTESW/
• https://security.gentoo.org/glsa/202208-15Third Party Advisory
• https://www.openwall.com/lists/oss-security/2021/02/22/1Exploit, Mailing List, Third Party Advisory

Published

Feb 23, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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