CVE-2026-92387

never-ending loop via server response omission

Published Oct 20, 2026 CVSS 3.1 · 8.1 High EPSS 1.0% KEV · Not listed
Description
By permanently omitting the final control-response line, a malicious FTP,
IMAP, POP3, or SMTP server can exploit libcurl and completely bypass its
configured transfer timeout mechanism, indefinitely blocking all concurrent
transfers bound to the same multi-handle.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8927-1 curl vulnerabilities
Ubuntu USN Ubuntu USN USN-8927-2 curl vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Description A flaw was found in curl. When communicating with a malicious server using protocols such as FTP, IMAP, POP3, or SMTP, the server can trigger an infinite loop by continuously transmitting data while omitting the final control response line. This behavior bypasses configured transfer timeouts, indefinitely blocking concurrent transfers and resulting in a Denial of Service (DoS). By permanently omitting the final control-response line, a malicious FTP, IMAP, POP3, or SMTP server can exploit libcurl and completely bypass its configured transfer timeout mechanism, indefinitely blocking all concurrent transfers bound to the same multi-handle.
Title curl: curl: never-ending loop via server response omission never-ending loop via server response omission
References
Type Values Removed Values Added
First Time appeared Curl
Curl curl
Vendors & Products Curl
Curl curl
Type Values Removed Values Added
Description A flaw was found in curl. When communicating with a malicious server using protocols such as FTP, IMAP, POP3, or SMTP, the server can trigger an infinite loop by continuously transmitting data while omitting the final control response line. This behavior bypasses configured transfer timeouts, indefinitely blocking concurrent transfers and resulting in a Denial of Service (DoS).
Title curl: curl: never-ending loop via server response omission
Weaknesses CWE-835
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Low

Weaknesses

Sources

Status
PUBLISHED
Assigner
curl
Published
Updated
Oct 29, 2026, 7:02 PM
Reserved
Sep 16, 2026, 8:12 AM
Status
Awaiting Analysis
Published
Oct 20, 2026, 9:17 PM
Modified
Oct 29, 2026, 7:17 PM
Severity
Low
Public date
Oct 14, 2026, 12:00 PM