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CVE-2025-5399

WebSocket endless loop

Published: Jun 7, 2025Updated: Jul 30, 2025 Sources: CVE List NVD BDUCWE-835
7.5HIGH
NVD MITRE
EPSS Score
1.3%
Top 32.6%
CISA KEV
Not in KEV
Exploits
1 Known
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-835

Affected Products

curl
oss-project·USaka libcurl, wcurl
curlLibraryLibrary
OSS Libraries / generic-library
haxx
oss-project·SEaka haxx.se
curl
OSS Libraries
Daniel Stenberg
individual-devaka daniel stenberg (curl author), daniel.haxx.se
LibcurlLibraryLibrary
OSS Libraries / generic-library

Exploitability

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://curl.se/docs/CVE-2025-5399.json
curl.se
https://curl.se/docs/CVE-2025-5399.html
curl.se
https://hackerone.com/reports/3168039
hackerone.com
and 3 more references View all →

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