CVE-2017-16943

Impact:
Critical
Public Date:
2017-11-23
CWE:
CWE-416
Bugzilla:
1517680: CVE-2017-16943 exim: use-after-free in receive_msg function via vectors involving BDAT commands

The MITRE CVE dictionary describes this issue as:

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.

Find out more about CVE-2017-16943 from the MITRE CVE dictionary dictionary and NIST NVD.

CVSS v3 metrics

NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.

CVSS3 Base Score 9.8
CVSS3 Base Metrics CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity Impact High
Availability Impact High

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 5 exim Not affected

Mitigation

if you are running Exim 4.88 or newer, then in the main section of your Exim configuration, set:

chunking_advertise_hosts =

This disables advertising the ESMTP CHUNKING extension, making the BDAT verb unavailable and avoids letting an attacker apply the logic.

Last Modified

CVE description copyright © 2017, The MITRE Corporation

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