Apache HTTP Server up to 2.4.48 mod_proxy server-side request forgery

Summaryinfo

A vulnerability, which was classified as critical, was found in Apache HTTP Server up to 2.4.48. This affects an unknown part of the component mod_proxy. Executing a manipulation can lead to server-side request forgery. This vulnerability is registered as CVE-2021-40438. It is possible to launch the attack remotely. Furthermore, an exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Apache HTTP Server up to 2.4.48 (Web Server). This vulnerability affects some unknown functionality of the component mod_proxy. The manipulation with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was published 09/16/2021. The advisory is shared for download at httpd.apache.org. This vulnerability was named CVE-2021-40438 since 09/02/2021. Technical details are unknown but an exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/23/2026).

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 294771 (MiracleLinux 8 : httpd:2.4 (AXSA:2021-2541:01)), which helps to determine the existence of the flaw in a target environment. This issue was added on 12/01/2021 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 12/15/2021:

Apply updates per vendor instructions.

Upgrading to version 2.4.49 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (294771). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Web Server

Vendor

• Apache

Name

• HTTP Server

Version

• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3
• 2.4.4
• 2.4.5
• 2.4.6
• 2.4.7
• 2.4.8
• 2.4.9
• 2.4.10
• 2.4.11
• 2.4.12
• 2.4.13
• 2.4.14
• 2.4.15
• 2.4.16
• 2.4.17
• 2.4.18
• 2.4.19
• 2.4.20
• 2.4.21
• 2.4.22
• 2.4.23
• 2.4.24
• 2.4.25
• 2.4.26
• 2.4.27
• 2.4.28
• 2.4.29
• 2.4.30
• 2.4.31
• 2.4.32
• 2.4.33
• 2.4.34
• 2.4.35
• 2.4.36
• 2.4.37
• 2.4.38
• 2.4.39
• 2.4.40
• 2.4.41
• 2.4.42
• 2.4.43
• 2.4.44
• 2.4.45
• 2.4.46
• 2.4.47
• 2.4.48

License

• open-source

Website

• Vendor: https://www.apache.org/

CPE 2.3info

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CPE 2.2info

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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