Vulnerability identifier: #VU18108

Vulnerability risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-0197

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 an error within the mod_http2 module when processing update requests from http/1.1 to http/2, if this was not the first request on a connection. A remote attacker can send specially crafted requests to the affected server and perform denial of service attack.

Successful exploitation of the vulnerability requires that HTTP/2 protocol is enabled for a "http:" host or H2Upgrade is enabled for h2 on a "https:" host.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache HTTP Server: 2.4.34 - 2.4.38

---

External links
http://www.apache.org/dist/httpd/CHANGES_2.4

---

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.