https://github.com/curl/curl

CVE-2021-22890

MEDIUM 4.3

At a glance

Source: NVD
EPSS: EPSS 3.06 % · percentile 88 (2026-10-29)
State: PUBLISHED
Published: 2021-04-01 17:46 UTC
Updated: 2026-10-14 10:15 UTC
Assigner: hackerone
NVD status: Modified

Search on…

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.

Weaknesses (CWE)

CWE-300 — Channel Accessible by Non-Endpoint
CWE-290 — Authentication Bypass by Spoofing

References

Scores

Version	Score	Vector	Scored by
CVSS 3.1	MEDIUM 4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N	CISA-ADP
CVSS 3.1	LOW 3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N	NVD · nvd@nist.gov (Primary)
CVSS 3.1	MEDIUM 4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N	NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
CVSS 2.0	MEDIUM 4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N	NVD · nvd@nist.gov (Primary)

European references

ENISA EUVD · EUVD-2021-10022
GCVE · GCVE-0-2021-22890

CERT-FR advisories

CERTFR-2023-AVI-1015 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
CERTFR-2023-AVI-0701 — Multiples vulnérabilités dans Splunk · cert.ssi.gouv.fr
CERTFR-2023-AVI-0428 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
CERTFR-2022-AVI-216 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:haxx:libcurl:*:*:*:*:*:*:*:* ≥ 7.63.0 ≤ 7.75.0
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*
cpe:2.3:h:netapp:hci_storage_node:-:*:*:*:*:*:*:*
cpe:2.3:o:broadcom:fabric_operating_system:-:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:a:siemens:sinec_infrastructure_network_services:*:*:*:*:*:*:*:* < 1.0.1.1
cpe:2.3:a:oracle:communications_billing_and_revenue_management:12.0.0.3.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:essbase:21.2:*:*:*:*:*:*:*
cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:* ≥ 8.2.0 < 8.2.12
cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:* ≥ 9.0.0 < 9.0.6
cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:*

Affected products

Product	Versions
https://github.com/curl/curl	affected 7.63.0 to and including 7.75.0

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD

🟡 https://github.com/curl/curl