Evidence · DiggingBeagle record
Check Point: ChatGPT Lockdown HTML Preview bypass and egress
A nested iframe in ChatGPT HTML Preview could invoke a child contentWindow.open path that bypassed the parent popup interception logic while sandbox policy still permitted popup escape. Check Point demonstrated controlled outbound web egress and phishing-style popups under this configuration, with an Electron client variant opening without gesture. OpenAI removed the unsafe permissions in September 2026; the experiment was not a reported user compromise. Research/disclosure claims are specific to the documented settings; do not infer unreported victims or additional compromise.
- Source role
- primary disclosure
Evidence record
A nested iframe in ChatGPT HTML Preview could invoke a child contentWindow.open path that bypassed the parent popup interception logic while sandbox policy still permitted popup escape. Check Point demonstrated controlled outbound web egress and phishing-style popups under this configuration, with an Electron client variant opening without gesture. OpenAI removed the unsafe permissions in September 2026; the experiment was not a reported user compromise. Research/disclosure claims are specific to the documented settings; do not infer unreported victims or additional compromise.
Claim-level citations (3)
- supportsChatGPT HTML Preview nested frames permitted popup escape and outbound egress: Check Point demonstrated controlled outbound web egress and phishing-style popups under this configuration, with an Electron client variant opening without gesture. OpenAI removed the unsafe permissions in September 2026; the experiment was not a reported user compromise.
Check Point Blog: lockdown HTML Preview bypass; nested iframe window.open and mitigation
- supportsChatGPT HTML Preview nested frames permitted popup escape and outbound egress: A nested iframe in ChatGPT HTML Preview could invoke a child contentWindow.open path that bypassed the parent popup interception logic while sandbox policy still permitted popup escape.
Check Point Blog: lockdown HTML Preview bypass; nested iframe window.open and mitigation
- supportsChatGPT HTML Preview nested frames permitted popup escape and outbound egress: Check Point reports that the HTML Preview popup-escape route was addressed on September 18, 2026 by removing sandbox popup permissions; its later November disclosure describes the previously reproducible path, not confirmed post-fix exploitation.
HTML Preview frame sandbox permissions and September 18 remediation