OkCupid had a CSRF vulnerability (via) Good write-up of a (now fixed) CSRF vulnerability on OkCupid. Their site worked by POSTing JSON objects to an API. JSON POSTs are usually protected against CSRF because they can only be sent using fetch()
or XMLHttpRequest
, which are protected by the same-origin policy. Yan Zhu notes that you can use the enctype="text/plain"
attribute on a form (introduced in HTML5) and a crafty hidden input element with name='{"foo":"' value='bar"}'
to construct JSON in an off-site form, which enabled CSRF attacks.
Recent articles
- The Summer of Johann: prompt injections as far as the eye can see - 15th August 2025
- Open weight LLMs exhibit inconsistent performance across providers - 15th August 2025
- LLM 0.27, the annotated release notes: GPT-5 and improved tool calling - 11th August 2025