Vulnerability identifier: #VU35880

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-2020-9490

CWE-ID: CWE-20

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 insufficient validation of user-supplied input when processing Cache-Digest header in HTTP/2 request. A remote attacker can pass specially crafted HTTP/2 request to the Apache HTTP Server, trigger the server to send the HTTP/2 PUSH and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Configuring the HTTP/2 feature via "H2Push off" will mitigate this vulnerability for unpatched servers.

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-2020-9490

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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.