{"id":"CVE-2026-117645","title":"Phoenix.HTML vulnerable to attribute injection via unvalidated attribute names in attributes_escape/1","summary":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in phoenixframework phoenix_html allows an attacker who controls attribute names to inject attributes and script into rendered HTML via Ph…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","cvssSource":"cna","cwe":["CWE-79"],"vendor":"phoenixframework","product":"phoenix_html","affected":["phoenix_html >= 1.0.0 < 3.3.5","phoenix_html >= 4.0.0 < 4.4.0","phoenixframework/phoenix_html >= 6ad3a1d7960891a468d54636054a98e11dfb5111 < *"],"published":"2026-10-30","updated":"2026-10-30","sourceUpdated":"2026-10-30T20:25:06.758Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-117645","references":[{"url":"https://cna.erlef.org/cves/CVE-2026-117645.html","label":"EEF CNA record for CVE-2026-117645"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-117645","label":"OSV record EEF-CVE-2026-117645"},{"url":"https://github.com/phoenixframework/phoenix_html/commit/6ad3a1d7960891a468d54636054a98e11dfb5111","label":"Introducing commit 6ad3a1d in phoenixframework/phoenix_html"},{"url":"https://github.com/phoenixframework/phoenix_html/commit/d9e4e6b2d9be49e25fb6d6b4fdbb2008174f01a6","label":"Fix commit d9e4e6b in phoenixframework/phoenix_html"},{"url":"https://github.com/phoenixframework/phoenix_html/commit/a47dc8944a773b7e9273d9691dc6744ec793f1de","label":"Fix commit a47dc89 in phoenixframework/phoenix_html"}],"tags":["cve.org"],"epss":0.00315,"epssPercentile":0.24544,"ingestedAt":"2026-11-05T16:24:31.460Z","slug":"CVE-2026-117645","body":"## Overview\n\nImproper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in phoenixframework phoenix_html allows an attacker who controls attribute names to inject attributes and script into rendered HTML via Phoenix.HTML.attributes_escape/1.\n\nattributes_escape/1 in lib/phoenix_html.ex escapes attribute values but not attribute names. key_escape/1 passes a binary key through html_escape, which neutralizes quotes and angle brackets but not whitespace, so a key such as x onmouseover ends the attribute and starts a new one. An atom key is only dasherized, so any character passes, including quotes and >. Nested data, aria and phx keys take the same paths. An application is affected when it builds attribute keys from untrusted input and renders them through HEEx <tag {@attrs}>, content_tag/3, or a direct call. Before 3.0.0 the same code lived in Phoenix.HTML.Tag.\n\nThis issue affects phoenix_html: from 1.0.0 before 3.3.5 and from 4.0.0 before 4.4.0.\n\n## Affected\n\n- `phoenix_html >= 1.0.0 < 3.3.5`\n- `phoenix_html >= 4.0.0 < 4.4.0`\n- `phoenixframework/phoenix_html >= 6ad3a1d7960891a468d54636054a98e11dfb5111 < *`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nDo not derive attribute names from untrusted input. Where dynamic attribute keys are needed, check each key against an allow list, or against a pattern such as ^[a-zA-Z][a-zA-Z0-9:._-]*$, before passing the map to attributes_escape/1 or a HEEx {@attrs} expression. Do not create atoms from request data.","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}