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.
CVE-2021-22890
Score 3.7 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 3.7; sources differ by 0.0.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 3.7
- EG Score
- 3.7(medium)
- EPSS
- 86.4%
- KEV
- Not listed
Published
April 1, 2021
Last Modified
June 9, 2025
References (18)
- support@hackeronehttps://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- support@hackeronehttps://curl.se/docs/CVE-2021-22890.html
- support@hackeronehttps://hackerone.com/reports/1129529
- support@hackeronehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/
- support@hackeronehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/
- support@hackeronehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/
- support@hackeronehttps://security.gentoo.org/glsa/202105-36
- support@hackeronehttps://security.netapp.com/advisory/ntap-20210521-0007/
- support@hackeronehttps://www.oracle.com//security-alerts/cpujul2021.html
- af854a3a-2127-422b-91ae-364da2661108https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- af854a3a-2127-422b-91ae-364da2661108https://curl.se/docs/CVE-2021-22890.html
- af854a3a-2127-422b-91ae-364da2661108https://hackerone.com/reports/1129529
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libcurl4-openssl-dev (7.47.0-1ubuntu2.19) @ xenial | 2026-05-26 | ubuntu |
| redhat | jbcs-httpd24-curl | 2021-06-17 | redhat |
| redhat | jbcs-httpd24-mod_security-0:2.9.2-63.GA.jbcs.el7 | 2021-06-17 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(4)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2021-228902023-03-10
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.
- Red HatRHSA-2021:2471LOW2021-03-31
RHSA-2021:2471 — Low
- Red HatRHSA-2021:2472LOW2021-03-31
RHSA-2021:2472 — Low
- UbuntuUSN-4898-1MEDIUM
curl vulnerabilities
Data Freshness Timeline
(refreshed 9× in last 7d / 42× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:07 UTCEPSS rescore
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- 2026-07-01 06:18 UTCOSV refresh
- 2026-06-30 23:20 UTCEPSS rescore
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- 2026-06-23 21:31 UTCEPSS rescore
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- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 10:43 UTCOSV refresh
- 2026-06-12 23:10 UTCEPSS rescore
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- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-26 18:55 UTCEG score recompute
- 2026-05-26 18:55 UTCVendor advisory
- 2026-05-26 18:55 UTCGHSA enrichment
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-24 16:49 UTCEPSS rescore
Frequently asked(5)
What is CVE-2021-22890?
When was CVE-2021-22890 disclosed?
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What is the CVSS score of CVE-2021-22890?
How do I remediate CVE-2021-22890?
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