Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-22890

CVE-2021-22890LOW

n/a https://github.com/curl/curl — 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 o…

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   H   N   N  U  N  L  N    3.7   .0306   87.4     —

AFFECTED
  Product                       Versions                          Fixed
  https://github.com/curl/curl  7.63.0 to and including 7.75.0 –  —

TIMELINE
  Jan 6   Reserved by hackerone
  Apr 1   Published (CNA: hackerone)
  Oct 14  EXPLOIT PUBLISHED — CVE-2021-22890 (https://github.com/curl/curl). Public exploit reference added.
  Oct 14  RESCORED — CVE-2021-22890 (https://github.com/curl/curl). CVSS 4.3 → 3.7 (NVD).

CWE-290, CWE-300 · CNA: hackerone · CVSS v3.1 · 11 references · NVD status: Modified

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.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
January 6, 2021	Reserved	Reserved by hackerone
April 1, 2021	Published	Published (CNA: hackerone)
October 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2021-22890 (https://github.com/curl/curl). Public exploit reference added.
October 14, 2026	RESCORED	RESCORED — CVE-2021-22890 (https://github.com/curl/curl). CVSS 4.3 → 3.7 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	https://github.com/curl/curl	—	7.63.0 to and including 7.75.0	—

Weaknesses

CWE-290 · CWE-300

References (11)

https://cert-portal.siemens.com/productcert/html/ssa-389290.html
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf [Patch, Third Party Advisory]
https://curl.se/docs/CVE-2021-22890.html [Patch, Vendor Advisory]
https://hackerone.com/reports/1129529 [Exploit, Issue Tracking, Patch, Third Party Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/ [Mailing List, Third Party Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/ [Mailing List, Third Party Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/ [Mailing List, Third Party Advisory]
https://security.gentoo.org/glsa/202105-36 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20210521-0007/ [Third Party Advisory]
https://www.oracle.com//security-alerts/cpujul2021.html [Third Party Advisory]

Authoritative record: CVE-2021-22890 at cve.org

Weaknesses: CWE-290 · CWE-300

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-22890 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.