CVE-2025-5399

7.5 highEPSS 1.4%

High (7.5) in haxx curl. 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.

Severity

CVSS 3.1

7.5 high

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

EPSS: 1.4% chance of exploitation in the next 30 days; higher than 72% of CVEs (scores of 2026-10-31)
CWE: CWE-835
Published: 2025-06-07
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

haxx:curl

References

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

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