CVE-2025-5399 Information

Description

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.

Reference

cve@curl.se http://www.openwall.com/lists/oss-security/2025/06/04/2 https://curl.se/docs/CVE-2025-5399.html https://curl.se/docs/CVE-2025-5399.json https://hackerone.com/reports/3168039 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.