Summary
SwiftNIO vulnerable to Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
NIOHTTP1 and projects using it for generating HTTP responses, including SwiftNIO, can be subject to a HTTP Response Injection attack. This occurs when a HTTP/1.1 server accepts user generated input from an incoming request and reflects it into a HTTP/1.1 response header in some form. A malicious user can add newlines to their input (usually in encoded form) and "inject" those newlines into the returned HTTP response.
This capability allows users to work around security headers and HTTP/1.1 framing headers by injecting entirely false responses or other new headers. The injected false responses may also be treated as the response to subsequent requests, which can lead to XSS, cache poisoning, and a number of other flaws.
This issue was resolved by adding a default channel handler that polices outbound headers. This channel handler is added by default to channel pipelines, but can be removed by users if they are doing this validation themselves.
Impact
CVE-2022-3215 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.42.0, 2.39.1, 2.29.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
github.com/apple/swift-nio to 2.42.0 or later; github.com/apple/swift-nio to 2.39.1 or later; github.com/apple/swift-nio to 2.29.1 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2022-3215? CVE-2022-3215 is a medium-severity security vulnerability in github.com/apple/swift-nio (swift), affecting versions >= 2.41.0, < 2.42.0. It is fixed in 2.42.0, 2.39.1, 2.29.1.
- How severe is CVE-2022-3215? CVE-2022-3215 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/apple/swift-nio are affected by CVE-2022-3215? github.com/apple/swift-nio (swift) versions >= 2.41.0, < 2.42.0 is affected.
- Is there a fix for CVE-2022-3215? Yes. CVE-2022-3215 is fixed in 2.42.0, 2.39.1, 2.29.1. Upgrade to this version or later.
- Is CVE-2022-3215 exploitable, and should I be worried? Whether CVE-2022-3215 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-3215 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-3215?
- Upgrade
github.com/apple/swift-nioto 2.42.0 or later - Upgrade
github.com/apple/swift-nioto 2.39.1 or later - Upgrade
github.com/apple/swift-nioto 2.29.1 or later
- Upgrade