Apache 2.4.x < 2.4.27 Multiple Vulnerabilities

critical Nessus Plugin ID 101788


The remote web server is affected by multiple vulnerabilities.


According to its banner, the version of Apache running on the remote host is 2.4.x prior to 2.4.27. It is, therefore, affected by the following vulnerabilities :

- A denial of service vulnerability exists in httpd due to a failure to initialize or reset the value placeholder in [Proxy-]Authorization headers of type 'Digest' before or between successive key=value assignments by mod_auth_digest. An unauthenticated, remote attacker can exploit this, by providing an initial key with no '=' assignment, to disclose sensitive information or cause a denial of service condition. (CVE-2017-9788)

- A read-after-free error exists in httpd that is triggered when closing a large number of connections. An unauthenticated, remote attacker can exploit this to have an unspecified impact. (CVE-2017-9789)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.


Upgrade to Apache version 2.4.27 or later.

See Also



Plugin Details

Severity: Critical

ID: 101788

File Name: apache_2_4_27.nasl

Version: 1.15

Type: combined

Agent: windows, macosx, unix

Family: Web Servers

Published: 7/18/2017

Updated: 4/11/2022

Configuration: Enable thorough checks

Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent

Risk Information


Risk Factor: Medium

Score: 6.0


Risk Factor: Medium

Base Score: 6.4

Temporal Score: 4.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:P

CVSS Score Source: CVE-2017-9788


Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:apache:http_server, cpe:/a:apache:httpd

Required KB Items: installed_sw/Apache

Exploit Ease: No known exploits are available

Patch Publication Date: 7/11/2017

Vulnerability Publication Date: 7/11/2017

Reference Information

CVE: CVE-2017-9788, CVE-2017-9789

BID: 99568, 99569