CVE-2021-22890

Public Exploit

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.

Categories

3.7
CVSS
Severity: Low
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.09%
Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory gentoo.org Vendor Advisory curl.se
Affected: n/a https://github.com/curl/curl
Published at:
Updated at:

References

Link Tags
https://hackerone.com/reports/1129529 patch exploit third party advisory issue tracking
https://curl.se/docs/CVE-2021-22890.html patch vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/ vendor advisory mailing list third party advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/ vendor advisory mailing list third party advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/ vendor advisory mailing list third party advisory
https://security.gentoo.org/glsa/202105-36 third party advisory vendor advisory
https://www.oracle.com//security-alerts/cpujul2021.html third party advisory
https://security.netapp.com/advisory/ntap-20210521-0007/ third party advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf third party advisory patch

Frequently Asked Questions

What is the severity of CVE-2021-22890?
CVE-2021-22890 has been scored as a low severity vulnerability.
How to fix CVE-2021-22890?
To fix CVE-2021-22890, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-22890 being actively exploited in the wild?
It is possible that CVE-2021-22890 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-22890?
CVE-2021-22890 affects n/a https://github.com/curl/curl.
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