CVE-2021-22890

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.

How to fix CVE-2021-22890

To remediate CVE-2021-22890, upgrade the affected package to a fixed version below.

• —upgrade to 7.76.0-r0 or later
• —upgrade to 7.74.0-1.2 or later

Is CVE-2021-22890 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 7.76.0-r0
• from 0, < 7.74.0-1.2

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2021-22890
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-22890