The client-side escapeForHtml() function in KimaiEscape.js, introduced in commit 89bfa82c (#2959) to fix a JavaScript XSS vulnerability, only escapes <, >, and & but does not escape " (double quote) or ' (single quote). When user-controlled data (profile alias) is placed in an HTML attribute context (title="__DISPLAY__") via the team member form prototype and rendered through innerHTML, the missing quote escaping allows HTML attribute injection, resulting in Stored XSS.
Incomplete security patch. The escapeForHtml() function was meant to prevent XSS but missed quote characters, which are critical for HTML attribute context escaping.
Vulnerable code — assets/js/plugins/KimaiEscape.js:29-33:
const tagsToReplace = {
'&': '&',
'<': '<',
'>': '>',
// MISSING: '"': '"'
// MISSING: "'": '''
};
Affected code files:
assets/js/plugins/KimaiEscape.js:24-38 — incomplete escape functionassets/js/forms/KimaiTeamForm.js:77,86 — replacement + innerHTMLtemplates/macros/widgets.html.twig:126 — title="{{ tooltip }}" in avatar macrotemplates/form/blocks.html.twig:104 — {{ widgets.avatar('__INITIALS__', '__COLOR__', '__DISPLAY__') }}Please extract the uploaded compressed file before proceeding
{
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-15T19:46:35Z",
"nvd_published_at": "2026-04-17T23:16:12Z",
"severity": "MODERATE"
}