CVE-2022-3918

CVE-2022-3918 is a high-severity vulnerability in Apple Swift Foundation with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-74.

Key facts

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.

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 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2022-3918 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-3918?
CVE-2022-3918 affects Apple Swift Foundation. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-3918?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2022-3918 published?
CVE-2022-3918 was published on 2023-01-20 and last updated on 2026-06-17.

References

Affected products (1)

Other CWE-74 (Improper Neutralization of Special Elements (Injection)) vulnerabilities

Browse all CWE-74 (Improper Neutralization of Special Elements (Injection)) vulnerabilities →