CVE-2021-22946

curl: Requirement to use TLS not properly enforced for IMAP, POP3, and FTP protocols

Published Sep 29, 2021 CVSS 3.1 · 7.5 High EPSS 4.5% KEV · Not listed
Description
A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (`--ssl-reqd` on the command line or`CURLOPT_USE_SSL` set to `CURLUSESSL_CONTROL` or `CURLUSESSL_ALL` withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations **withoutTLS** contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-2773-1 curl security update
Debian DLA Debian DLA DLA-3085-1 curl security update
Debian DSA Debian DSA DSA-5197-1 curl security update
Ubuntu USN Ubuntu USN USN-5079-1 curl vulnerabilities
Ubuntu USN Ubuntu USN USN-5079-2 curl vulnerabilities
History

Subscriptions

Apple Macos
Debian Debian Linux
Fedoraproject Fedora
Haxx Curl
Netapp Cloud Backup Clustered Data Ontap H300e H300e Firmware H300s H300s Firmware H410s H410s Firmware H500e H500e Firmware H500s H500s Firmware H700e H700e Firmware H700s H700s Firmware Oncommand Insight Oncommand Workflow Automation Snapcenter Solidfire Baseboard Management Controller Solidfire Baseboard Management Controller Firmware
Oracle Commerce Guided Search Communications Cloud Native Core Binding Support Function Communications Cloud Native Core Console Communications Cloud Native Core Network Function Cloud Native Environment Communications Cloud Native Core Network Repository Function Communications Cloud Native Core Network Slice Selection Function Communications Cloud Native Core Security Edge Protection Proxy Communications Cloud Native Core Service Communication Proxy Mysql Server Peoplesoft Enterprise Peopletools
Redhat Enterprise Linux Rhel Dotnet Rhel Eus
Siemens Sinec Infrastructure Network Services
Splunk Universal Forwarder
Weaknesses

Sources

Status
PUBLISHED
Assigner
hackerone
Published
Updated
Oct 14, 2026, 11:29 AM
Reserved
Jan 6, 2021, 12:00 AM
Status
Modified
Published
Sep 29, 2021, 8:15 PM
Modified
Oct 14, 2026, 12:17 PM
Severity
Moderate
Public date
Sep 15, 2021, 12:00 AM