CVE-2021-44143

Publication date 22 November 2021

Last updated 11 July 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was found in mbsync in isync 1.4.0 through 1.4.3. Due to an unchecked condition, a malicious or compromised IMAP server could use a crafted mail message that lacks headers (i.e., one that starts with an empty line) to provoke a heap overflow, which could conceivably be exploited for remote code execution.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
isync	25.10 questing	Vulnerable
	25.04 plucky	Ignored end of life, was needed
	24.10 oracular	Ignored end of life, was needed
	24.04 LTS noble	Vulnerable
	23.10 mantic	Ignored end of life, was needed
	23.04 lunar	Ignored end of life, was needed
	22.10 kinetic	Ignored end of life, was needed
	22.04 LTS jammy	Vulnerable
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Ignored end of standard support

Notes

seth-arnold

I can't find a fix for this in the source browser; I'm marking jammy as 'needed' and others as 'not-affected' based on the version number, but I distrust the upper end of the '1.4.0 through 1.4.3' range given in the CVE description. I suspect "unfixed" is the more correct upper range.

Severity score breakdown

Parameter	Value
Base score	9.8 · Critical
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H