CVE-2019-15846

Publication date 6 September 2019

Last updated 24 July 2024

Ubuntu priority

Why this priority?

Cvss 3 Severity Score

Score breakdown

Exim before 4.92.2 allows remote attackers to execute arbitrary code as root via a trailing backslash.

From the Ubuntu Security Team

It was discovered that Exim incorrectly handled certain decoding operations. A remote attacker could possibly use this issue to execute arbitrary commands.

Mitigation

Add - as part of the mail ACL (the ACL referenced by the main config option "acl_smtp_mail"): deny condition = ${if eq{\\}{${substr{-1}{1}{$tls_in_sni}}}} deny condition = ${if eq{\\}{${substr{-1}{1}{$tls_in_peerdn}}}}

Status

Show unmaintained releases

Package	Ubuntu Release	Status
exim4	19.04 disco	Fixed 4.92-4ubuntu1.3
	18.04 LTS bionic	Fixed 4.90.1-1ubuntu1.4
	16.04 LTS xenial	Fixed 4.86.2-2ubuntu2.5
	14.04 LTS trusty	Fixed 4.82-3ubuntu2.4+esm1 Ubuntu Pro

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
exim4	Upstream: 2600301

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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H