CVE-2021-22890
LOWEPSS 87th pctlDescription
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
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 87% of all known CVEs.
References
Related Vulnerabilities
Other CWE-300 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2009-3555 | Critical | 9.8 | 87% | - | Fix |
| CVE-2017-12150 | High | 7.4 | 13% | - | Fix |
| CVE-2017-12151 | High | 7.4 | 4.6% | - | Fix |
| CVE-2020-10749 | Medium | 6.0 | 2.4% | - | Fix |
| CVE-2017-7480 | Critical | 9.8 | 2.3% | - | Fix |
| CVE-2021-32926 | High | 7.5 | 2.2% | - | - |
Common questions
How do I fix CVE-2021-22890?
Published advisories record a fix for 7 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-22890 being actively exploited?
Not that we know of. CVE-2021-22890 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 3.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 87% of all scored CVEs.
How severe is CVE-2021-22890?
CVE-2021-22890 has a CVSS v3 base score of 3.7, rated low. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-22890 affect?
Published advisories record a fix for curl (Debian), curl (Ubuntu), libcurl3 (Ubuntu), libcurl3-gnutls (Ubuntu), and 3 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-22890
Markdown
[](https://tridentstack.com/cve/CVE-2021-22890)HTML
<a href="https://tridentstack.com/cve/CVE-2021-22890"><img src="https://tridentstack.com/cve/badge/CVE-2021-22890.svg" alt="CVE-2021-22890"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-06-09.