CVE-2023-38709

Faulty input validation in the core of Apache allows malicious or exploitable backend/content generators to split HTTP responses.

This issue affects Apache HTTP Server: through 2.4.58.

Weakness

The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

Affected Software

Name	Vendor	Start Version	End Version
Http_server	Apache	*	2.4.59 (excluding)
JBoss Core Services for RHEL 8	RedHat	jbcs-httpd24-httpd-0:2.4.57-15.el8jbcs	*
JBoss Core Services on RHEL 7	RedHat	jbcs-httpd24-httpd-0:2.4.57-15.el7jbcs	*
Red Hat Enterprise Linux 8	RedHat	httpd:2.4-8100020240612075645.489197e6	*
Red Hat Enterprise Linux 9	RedHat	httpd-0:2.4.62-1.el9	*
Text-Only JBCS	RedHat	httpd	*
Apache2	Ubuntu	devel	*
Apache2	Ubuntu	esm-infra/bionic	*
Apache2	Ubuntu	esm-infra/focal	*
Apache2	Ubuntu	esm-infra/xenial	*
Apache2	Ubuntu	focal	*
Apache2	Ubuntu	jammy	*
Apache2	Ubuntu	mantic	*
Apache2	Ubuntu	noble	*
Apache2	Ubuntu	oracular	*
Apache2	Ubuntu	plucky	*
Apache2	Ubuntu	questing	*
Apache2	Ubuntu	trusty/esm	*
Apache2	Ubuntu	upstream	*

Extended Description

Specified quantities include size, length, frequency, price, rate, number of operations, time, and others. Code may rely on specified quantities to allocate resources, perform calculations, control iteration, etc.

Potential Mitigations

Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

NVD	https://nvd.nist.gov/vuln/detail/CVE-2023-38709
CWE	https://cwe.mitre.org/data/definitions/1284.html

Improper Validation of Specified Quantity in Input

Weakness

Affected Software

Extended Description

Potential Mitigations

References