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CVE-2025-5399

WebSocket endless loop

Published: Jun 7, 2025Updated: Jul 30, 2025 Sources: CVE List NVD BDUCWE-835
NVD MITRE
7.5CVSSHIGH
EPSS Score
1.2%
Top 35.1%
CISA KEV
Not in KEV
Exploits
1 Known
Remediation
Patch Available

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.

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

LibcurlDaniel Stenberg
LibraryLibrary
OSS Libraries / generic-library
curlcurl
Library
OSS Libraries / generic-library
curlhaxxOSS Libraries
daniel stenbergindividual-devOSS Librariesaka daniel.haxx.se, daniel stenberg (curl author)
curloss-projectUSOSS Librariesaka libcurl, wcurl
haxxoss-projectSEOSS Librariesaka haxx.se

Attack Graph

Products CVE Techniques Tactics

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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

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://curl.se/docs/CVE-2025-5399.html
curl.se
https://github.com/curl/curl/commit/d1145df24de8f80e6b16
github.com
https://curl.se/docs/CVE-2025-5399.json
curl.se
and 3 more references View all →

Timeline

Published
Jun 7, 2025
Last Updated
Jul 30, 2025

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