Block link-local addresses in wp_http_validate_url()

[tanjiroK-coder]

wp_http_validate_url() is the validation layer used by WordPress's safe HTTP API (wp_safe_remote_get(), wp_safe_remote_post(), and related functions) to prevent requests to internal network destinations.

While the existing implementation blocks loopback and RFC1918 private address ranges, it does not reject the IPv4 link-local range (169.254.0.0/16).

This allows URLs resolving to addresses such as 169.254.169.254 (commonly used by cloud metadata services) to pass validation.

Changes

• Add validation logic to reject addresses in the 169.254.0.0/16 link-local range.

• Update the function documentation to include the newly blocked range.

• Add regression tests covering:

  • 169.254.169.254
  • 169.254.1.1

Impact

The link-local range is reserved for local network communication and should not be reachable through APIs intended to protect against SSRF.

Blocking this range aligns its handling with other reserved internal address ranges already denied by wp_http_validate_url() and prevents requests to cloud metadata endpoints from bypassing existing SSRF protections.

[github-actions]

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[github-actions]

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