What’s Vulnerable › Vulnerabilities
CVE-2021-22890
- Severity: low (CVSS 3.7 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 3.1% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2021-04-01 · updated 2026-10-14
- Weakness: CWE-300
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.
Affected products
- Brocade Fabric OS: all versions
- Debian Linux: 9.0
- Fedoraproject Fedora: 32, 33, 34
- curl: from 7.63.0 through 7.75.0
- NetApp Hci Management Node: all versions
- NetApp Hci Storage Node: all versions
- NetApp Solidfire: all versions
- Oracle Corporation Communications Billing and Revenue Management: 12.0.0.3.0
- Oracle Corporation Oracle Essbase: 21.2
- Siemens Sinec Infrastructure Network Services: before 1.0.1.1 — fixed in 1.0.1.1
- Splunk Universal Forwarder: from 8.2.0 before 8.2.12; from 9.0.0 before 9.0.6; 9.1.0 — fixed in 8.2.12, 9.0.6
How to fix
Upgrade to a fixed version: Siemens Sinec Infrastructure Network Services 1.0.1.1; Splunk Universal Forwarder 8.2.12, 9.0.6. Check the vendor advisory for mitigations.
References
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://curl.se/docs/CVE-2021-22890.html
- https://hackerone.com/reports/1129529
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/
- https://security.gentoo.org/glsa/202105-36
- https://security.netapp.com/advisory/ntap-20210521-0007/
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://curl.se/docs/CVE-2021-22890.html
- https://hackerone.com/reports/1129529
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