Name: CVE-2021-3657: Improper Restriction of Operations within the Bounds of a Memory Buffer
Creator: Rapid7
Published: 2022-02-18T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2021-3657, CWE-119, CVSS 9.8, EPSS 0.06799

A flaw was found in mbsync versions prior to 1.4.4. Due to inadequate handling of extremely large (>=2GiB) IMAP literals, malicious or compromised IMAP servers, and hypothetically even external email senders, could cause several different buffer overflows, which could conceivably be exploited for remote code execution.

CVSS Details

CVSS 3.1 Base Score: 9.8
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alpine Linux	—	Upgrade isync	Aug 22, 2024	Feb 18, 2022
Arch Linux	—	Upgrade to the latest version of Arch Linux	Jul 11, 2025	Feb 18, 2022
Debian	—	Upgrade isync	Jul 4, 2022	Feb 18, 2022
Gentoo Linux	—	Upgrade net-mail/isync.	Aug 11, 2022	Feb 18, 2022
Ubuntu	—	No solution exists	Jun 26, 2025	Feb 18, 2022

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CVSS Details

Covered by Rapid7

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