Home/CVE/Due to a mistake in libcurl's WebSocket code, a malicious server can send a particularly crafted packet which makes libc
CVE

CVE-2025-5399

Due to a mistake in libcurl's WebSocket code, a malicious server can send a particularly crafted packet which makes libc

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.

HIGH · CVSS 7.5 EPSS 0.00566
Act now
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules7 YARA rules0
⬡

Weakness Classification

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
▤

Affected Products & Versions

1
haxx curl>= 8.13.0 and < 8.14.1
⚠

Public Exploits & PoCs

1
pochackerone.com · 3168039hackerone.com
◈

Sigma Hunt Rules

7
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSuspicious Download and Execute Pattern via Curl/Wget
producthighSuspicious File Download From File Sharing Domain Via Curl.EXE
producthighSuspicious File Download From IP Via Curl.EXE
producthighCurl Download And Execute Combination
producthighSuspicious Curl.EXE Download
productmediumSuspicious Curl File Upload - Linux
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · 2499f714-1537-4658-8207-48ae4bb9eae9
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD07 Jun 2025 · 08:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

6
suse-csafSUSE-SU-2025:03198-1
suse-csafSUSE-SU-2025:20675-1
rhsaRHSA-2025:15699Low
rhsaRHSA-2025:16046Low
suse-csafopenSUSE-SU-2025:15213-1
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://curl.se/docs/CVE-2025-5399.htmlVendor Advisory
https://curl.se/docs/CVE-2025-5399.jsonVendor Advisory
http://www.openwall.com/lists/oss-security/2025/06/04/2Mailing ListThird Party Advisory
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