CVE-2021-22890
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.
Published Apr 1, 2021 · updated Oct 14, 2026 · haxx libcurl
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.
Timeline
Detection, updates, and resolution for this record.
Apr 1, 2021 · NIST NVD
Detected
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 HT
Oct 14, 2026 · NIST NVD
Updated
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 HT
Affected
- cpe broadcom/fabric operating systemversion unspecified
- cpe debian/debian linux9.0
- cpe fedoraproject/fedora32
- cpe fedoraproject/fedora33
- cpe fedoraproject/fedora34
- cpe haxx/libcurlversion unspecified
- cpe netapp/hci management nodeversion unspecified
- cpe netapp/hci storage nodeversion unspecified
- cpe netapp/solidfireversion unspecified
- cpe oracle/communications billing and revenue management12.0.0.3.0
- cpe siemens/sinec infrastructure network servicesversion unspecified
- cpe splunk/universal forwarderversion unspecified
Sources
- CVE.orgCVE-2021-22890
Official CVE identifier
cve.org - NIST NVDCVE-2021-22890
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
nvd.nist.gov