Vulnerability identifier: #VU35854

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-11993

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Apache HTTP Server
Server applications / Web servers

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper management of internal resources within the application while processing HTTP/2 requests with enabled trace/debug for HTTP/2 connections. A remote attacker can send specially crafted HTTP/2 requests to Apache HTTP Server and force it to make logging statements on wrong connection for certain traffic edge patterns. This results in concurrent use of memory pools for separate connections and triggers denial of service condition.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache HTTP Server: 2.4.20 - 2.4.43

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External links
http://httpd.apache.org/security/vulnerabilities_24.html#CVE-2020-11993

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.