CVE-2021-22890

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

3.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-04-01 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-14 11:16 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.1% in the next 30 days (EPSS).
• Severity: 3.7 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-04-01 18:15 UTC

Last modified

2026-10-14 11:16 UTC

Exploit probability

3.1% · EPSS, next 30 days

Weakness

CWE-300

Record status

Modified

Affected

• Haxx Libcurl ≤ 7.75.0
• Fedoraproject Fedora 32
• Fedoraproject Fedora 33
• Fedoraproject Fedora 34
• Netapp Hci Management Node
• Netapp Solidfire
• Netapp Hci Storage Node
• Broadcom Fabric Operating System

Attack profile CVSS 3.1 · 3.7

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-22890.md and follow it. Check whether this project is affected by CVE-2021-22890. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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