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.
" } ], "value": "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.\n\nThe 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.\n\nStandard 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.\n\nApplications that render user-supplied URLs (for example profile links, redirect targets, or external references) via <.link href={...}> are affected.\n\nThis issue affects phoenix_live_view: from 1.2.2 before 1.2.7." } ], "impacts": [ { "capecId": "CAPEC-63", "descriptions": [ { "lang": "en", "value": "CAPEC-63 Cross-Site Scripting (XSS)" } ] } ], "metrics": [ { "cvssV4_0": { "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "baseScore": 5.1, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "userInteraction": "ACTIVE", "vectorString": "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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-79", "description": "CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-07-14T04:15:01.996Z" }, "references": [ { "tags": [ "vendor-advisory", "related" ], "url": "https://github.com/phoenixframework/phoenix_live_view/security/advisories/GHSA-5cgh-g58j-m9cq" }, { "tags": [ "related" ], "url": "https://cna.erlef.org/cves/CVE-2026-58228.html" }, { "tags": [ "related" ], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-58228" }, { "tags": [ "patch" ], "url": "https://github.com/phoenixframework/phoenix_live_view/commit/86165533e311469a1b62093fd182d9d874de8106" } ], "source": { "discovery": "EXTERNAL" }, "title": "Scheme validation bypass in Phoenix.LiveView.Utils leads to XSS via <.link>", "workarounds": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "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.
" } ], "value": "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." } ], "x_generator": { "engine": "cvelib 1.8.0" } }, "adp": [ { "references": [ { "url": "https://github.com/phoenixframework/phoenix_live_view/security/advisories/GHSA-5cgh-g58j-m9cq", "tags": [ "exploit" ] } ], "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-07-13T18:58:11.563760Z", "id": "CVE-2026-58228", "options": [ { "Exploitation": "poc" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-13T18:58:51.407Z" } } ] } }