Description
curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.
Published: 2021-04-01
Score: 4.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-4881-1 curl security update
EUVD EUVD EUVD-2021-10022 curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.
Ubuntu USN Ubuntu USN USN-4898-1 curl vulnerabilities
History

Mon, 09 Jun 2025 16:15:00 +0000

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:L/A:N'}

ssvc

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

cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N'}


Subscriptions

Broadcom Fabric Operating System
Debian Debian Linux
Fedoraproject Fedora
Haxx Libcurl
Netapp Hci Management Node Hci Storage Node Solidfire
Oracle Communications Billing And Revenue Management Essbase
Redhat Jboss Core Services
Siemens Sinec Infrastructure Network Services
Splunk Universal Forwarder
cve-icon MITRE

Status: PUBLISHED

Assigner: hackerone

Published:

Updated: 2025-06-09T15:11:58.900Z

Reserved: 2021-01-06T00:00:00.000Z

Link: CVE-2021-22890

cve-icon Vulnrichment

Updated: 2024-08-03T18:58:25.687Z

cve-icon NVD

Status : Modified

Published: 2021-04-01T18:15:12.917

Modified: 2025-06-09T15:15:24.177

Link: CVE-2021-22890

cve-icon Redhat

Severity : Low

Publid Date: 2021-03-31T00:00:00Z

Links: CVE-2021-22890 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses