CVE-2025-22870: HTTP Proxy bypass using IPv6 Zone IDs in golang.org/x/net

March 12, 2025 (updated March 19, 2025)

Matching of hosts against proxy patterns can improperly treat an IPv6 zone ID as a hostname component. For example, when the NO_PROXY environment variable is set to “*.example.com”, a request to “[::1%25.example.com]:80` will incorrectly match and not be proxied.

References

github.com/advisories/GHSA-qxp5-gwg8-xv66
go-review.googlesource.com/q/project:net
go.dev/cl/654697
go.dev/issue/71984
nvd.nist.gov/vuln/detail/CVE-2025-22870
pkg.go.dev/vuln/GO-2025-3503

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