CVE-2026-3784: Haxx Curl

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection.

Affected products

• Haxx Curl: from 7.7, before 8.18.0 (fixed in 8.18.0)

Published 2026-03-11. Last modified 2026-09-15.