Severity
Exposure
Date of incident
ChatGPT DNS Exfill
reported
Tier -
A
ChatGPT runtime leaked via DNS — sandbox egress assumption failed at agent hop.
What Happened
Researchers abused DNS resolution path from ChatGPT code-analysis container to encode and leak conversation content; model assumed runtime had no outbound path and did not trigger user mediation.
Sumarry
Check Point Research disclosed ChatGPT data exfiltration via DNS side-channel from the purportedly isolated Python execution runtime; OpenAI deployed full fix February 20, 2026.
Detect
Egress allow-list on agent runtime; DNS anomaly detect
What Happened
Agent boundary deny on covert channels post-tool execution
Blekline //
Lineage block + egress policy on agent tool runtime
Without agent boundary //
Trust vendor sandbox marketing — no customer-controlled egress gate
