CVE-2021-29416: Portswigger Burp Suite

Medium severity, CVSS 6.5. EPSS: 1.1% chance of exploitation in the next 30 days.

An issue was discovered in PortSwigger Burp Suite before 2021.2. During viewing of a malicious request, it can be manipulated into issuing a request that does not respect its upstream proxy configuration. This could leak NetNTLM hashes on Windows systems that fail to block outbound SMB.

Affected products

• Portswigger Burp Suite: before 2021.2 (fixed in 2021.2)

Published 2021-03-29. Last modified 2026-06-17.