Semantic MediaWiki has reflected XSS in `Special:SearchByProperty` (`property` and `value` parameters)

Failure mode

The value parameter was reflected back into rendered output and error messaging paths without enough output-context encoding.

Remediation

• The form value is escaped before it is placed back into the input field.
• Derived error messages are also escaped before being rendered into HTML.

Maintenance note

Do not treat error text as trusted just because it originated from validation. Validation output can still be attacker-influenced.