CVE-2022-3918: A program using FoundationNetworking in swift-corelibs-foundation is potentially vulnerable to CRLF ( ) injection in URLRequest headers. In this vulne...

Description

A program using FoundationNetworking in swift-corelibs-foundation is potentially vulnerable to CRLF ( ) injection in URLRequest headers. In this vulnerability, a client can insert one or several CRLF sequences into a URLRequest header value. When that request is sent via URLSession to an HTTP server, the server may interpret the content after the CRLF as extra headers, or even a second request. For example, consider a URLRequest to http://example.com/ with the GET method. Suppose we set the URLRequest header "Foo" to the value "Bar Extra-Header: Added GET /other HTTP/1.1". When this request is sent, it will appear to the server as two requests: GET / HTTP/1.1 Foo: Bar Extra-Header: Added GET /other HTTP/1.1 In this manner, the client is able to inject extra headers and craft an entirely new request to a separate path, despite only making one API call in URLSession. If a developer has total control over the request and its headers, this vulnerability may not pose a threat. However, this vulnerability escalates if un-sanitized user input is placed in header values. If so, a malicious user could inject new headers or requests to an intermediary or backend server. Developers should be especially careful to sanitize user input in this case, or upgrade their version of swift-corelibs-foundation to include the patch below.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.78%

51.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-74

Affected Software

Vendor	Product	Versions
Apple	Swift Foundation	< 5.7.3

References

https://github.com/apple/swift-corelibs-foundation/security/advisories/GHSA-4pp3-mpf2-rj63Mitigation, Third Party Advisory
https://github.com/apple/swift-corelibs-foundation/security/advisories/GHSA-4pp3-mpf2-rj63Mitigation, Third Party Advisory

Timeline

Published: Jan 20, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-3918?

A program using FoundationNetworking in swift-corelibs-foundation is potentially vulnerable to CRLF ( ) injection in URLRequest headers. In this vulnerability, a client can insert one or several CRLF sequences into a URLRequest header value. When that request is sent via URLSession to an HTTP server, the server may interpret the content after the CRLF as extra headers, or even a second request. For example, consider a URLRequest to http://example.com/ with the GET method. Suppose we set the URLRequest header "Foo" to the value "Bar Extra-Header: Added GET /other HTTP/1.1". When this request is sent, it will appear to the server as two requests: GET / HTTP/1.1 Foo: Bar Extra-Header: Added GET /other HTTP/1.1 In this manner, the client is able to inject extra headers and craft an entirely new request to a separate path, despite only making one API call in URLSession. If a developer has total control over the request and its headers, this vulnerability may not pose a threat. However, this vulnerability escalates if un-sanitized user input is placed in header values. If so, a malicious user could inject new headers or requests to an intermediary or backend server. Developers should be especially careful to sanitize user input in this case, or upgrade their version of swift-corelibs-foundation to include the patch below.

How severe is CVE-2022-3918?

CVE-2022-3918 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.78% probability of exploitation in the next 30 days.

How do I fix CVE-2022-3918?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.