WebSocket endless loop
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.
02 / AFFECTED SOFTWARE
Affected packages
2 explicit affected versions
4 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
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.
05 / REFERENCES
Further evidence
- 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://github.com/CVEProject/cvelistV5/tree/main/cves/2025/5xxx/CVE-2025-5399.json
- https://hackerone.com/reports/3168039
- https://nvd.nist.gov/vuln/detail/CVE-2025-5399