CVE-2026-58228

Summary

Cross-site scripting vulnerability in phoenixframework phoenix_live_view allows an attacker to bypass URL scheme validation and execute JavaScript in a victim's browser session.

The Phoenix.LiveView.Utils.valid_destination!/2 and Phoenix.LiveView.Utils.valid_live_navigation_destination!/2 functions in lib/phoenix_live_view/utils.ex rely on an internal uri_scheme/1 helper that only detects a scheme when the input's first byte is an ASCII letter. Inputs beginning with an ASCII control character or space fall through to a nil-returning clause, causing the URL to be treated as a safe relative path.

Standard browsers implement the WHATWG URL parser, which strips leading C0 control and space characters before parsing. As a result, an input such as " javascript:alert(1)" is passed unchanged into <.link href={…}> and, when clicked, is parsed by the browser as a javascript: URL that executes attacker-controlled script in the victim's session.

Applications that render user-supplied URLs (for example profile links, redirect targets, or external references) via <.link href={…}> are affected.

This issue affects phoenix_live_view: from 1.2.2 before 1.2.7.

Affected Software

VendorProductVersion RangeStatus
phoenixframeworkphoenix_live_view1.2.2 < 1.2.7affected
phoenixframeworkphoenix_live_view4b63216ae68886db99cf7772af23372d76c40e7e < 86165533e311469a1b62093fd182d9d874de8106affected

Weaknesses

  • CWE-79: CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Workarounds

Strip leading ASCII control and space bytes (code points 0x00 through 0x20) from any untrusted URL before passing it to <.link href={…}>, or reject such inputs outright. This aligns application-level validation with the WHATWG URL parser used by browsers and prevents the scheme-detection bypass.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

Additional References

References