CVE-2021-22890

Published: 31 March 2021

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.

Priority

Medium

CVSS 3 base score: 3.7

Status

Package Release Status
curl
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 20.10 (Groovy Gorilla)
Released (7.68.0-1ubuntu4.3)
Ubuntu 20.04 LTS (Focal Fossa)
Released (7.68.0-1ubuntu2.5)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(code not present)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(code not present)
Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(code not present)
Patches:
Vendor: https://curl.se/EQo2A9nBnMI68.patch