CVE-2022-32148: Exposure of client IP addresses in net/http
Summary
CVE-2022-32148: Exposure of client IP addresses in net/http. Affects stdlib across 2 version ranges.
< 1.17.12
>= 1.18.0-0, < 1.18.4
Fixed in 1.17.12 or 1.18.4, depending on the release line you run. How to fix ↓
Also tracked for
- golang · Bitnami
- golang-1.15 · Debian:11
The same CVE-2022-32148 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
The net/http package is a part of the Go standard library and provides a set of functions and types for building HTTP servers and clients. It is widely used for developing web applications and services in the Go ecosystem. This vulnerability specifically affects the handling of client IP addresses in the net/http package.
Vulnerability Detail
The vulnerability (CVE-2022-32148) arises from a flaw in the httputil.ReverseProxy.ServeHTTP function. When a Request.Header map contains a nil value for the X-Forwarded-For header, the ReverseProxy incorrectly sets the client IP as the value of the X-Forwarded-For header, contrary to its documentation. This can lead to unintentional exposure of client IP addresses. Even when a Director function sets the X-Forwarded-For header value to nil, the ReverseProxy leaves the header unmodified, which is not the expected behavior.
How To Fix
Latest published version: go1.25.5 as of 22 Oct 2026
go get stdlib@vgo1.25.5Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 1.17.121.17.12go get stdlib@v1.17.12 -
>= 1.18.0-0, < 1.18.41.18.4go get stdlib@v1.18.4
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
If updating the Go version is not immediately feasible, a workaround can be implemented by manually modifying the ReverseProxy.ServeHTTP function to handle the X-Forwarded-For header correctly. Here is an example of a possible workaround:
func customServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.Header.Get("X-Forwarded-For") == "" {
r.Header.Set("X-Forwarded-For", r.RemoteAddr)
}
// Rest of the code...
}
Conclusion
The exposure of client IP addresses in the net/http package can have significant privacy and security implications. It is crucial to update the affected Go version to ensure proper handling of the X-Forwarded-For header. If immediate updating is not possible, implementing the provided workaround can mitigate the vulnerability temporarily. For further support and assistance in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for stdlib →
FAQ
This vulnerability can potentially expose client IP addresses, which may have privacy and security implications. It could allow an attacker to gather sensitive information about clients or perform IP-based attacks.
The vulnerability affects versions 0.x, 1.17.12, 1.18.0-0, and 1.18.4 of the Go standard library.
You can use the Vulert Playground (https://vulert.com/scanner) to check if your application is affected by this vulnerability. It analyzes your Gopkg.lock file and provides real-time alerts for open-source vulnerabilities in your software.
Yes, the fix for this vulnerability is available in Go versions 1.17.12 and 1.18.4. It is recommended to update to these versions to ensure the proper handling of client IP addresses.
Yes, you can implement the provided workaround by manually modifying the ReverseProxy.ServeHTTP function to handle the X-Forwarded-For header correctly. However, updating to the fixed versions is still strongly recommended.
References
Related vulnerabilities
Recent vulnerabilities recorded for stdlib.
