CVE-2025-5399

Name: CVE-2025-5399
Creator: NVD / NIST
Published: 2025-06-07T08:15:20.687+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.23%

Last modified Jun 17, 2026

CVE-2025-5399 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 1.23% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.23%

65.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-835

Affected Software

Vendor	Product	Versions
Haxx	Curl	>= 8.13.0, < 8.14.1

References

https://curl.se/docs/CVE-2025-5399.htmlVendor Advisory
https://curl.se/docs/CVE-2025-5399.jsonVendor Advisory
https://hackerone.com/reports/3168039Exploit, Issue Tracking, Third Party Advisory
http://www.openwall.com/lists/oss-security/2025/06/04/2Mailing List, Third Party Advisory

Timeline

Published: Jun 7, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-5399?

How severe is CVE-2025-5399?

CVE-2025-5399 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.23% probability of exploitation in the next 30 days.

How do I fix CVE-2025-5399?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-5399?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST