Phoenix Live View
CVE-2026-58228
MEDIUM
Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (EEF) · only source for this CVE.
CVSS VectorVendor: EEF
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
URL scheme validation bypass in Phoenix LiveView 1.2.2–1.2.6 allows unauthenticated attackers to inject javascript: URLs that execute in a victim's browser session when clicked. The root cause is a first-byte ASCII letter guard in the internal uri_scheme/1 helper: inputs prefixed with whitespace or C0 control characters bypass scheme detection entirely and are treated as safe relative paths, while WHATWG-compliant browsers silently strip those leading bytes before parsing — converting what LiveView sees as a harmless string into an executable javascript: URL. Applications rendering user-supplied URLs (profile links, redirect targets, external references) via the <.link href={...}> component are directly affected; no public exploit code has been identified at time of analysis, and a patched release (1.2.7) is available.
More in Phoenix Live View
View allSame weakness CWE-79 – Cross-site Scripting (XSS)
View allShare
External POC / Exploit Code
Leaving vuln.today