CVE-2025-5399: Haxx Curl

High severity, CVSS 7.5. EPSS: 1.4% chance of exploitation in the next 30 days.

Due to a mistake in libcurl's WebSocket code, a malicious server can send a particularly crafted packet which makes libcurl get trapped in an endless busy-loop. There is no other way for the application to escape or exit this loop other than killing the thread/process. This might be used to DoS libcurl-using application.

Affected products

• Haxx Curl: from 8.13.0, before 8.14.1 (fixed in 8.14.1)

Published 2025-06-07. Last modified 2026-06-17.