CVE-2023-28321

An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as Subject Alternative Name in TLS server certificates. curl can be built to use its own name matching function for TLS rather than one provided by a TLS library. This private wildcard matching function would match IDN (International Domain Name) hosts incorrectly and could as a result accept patterns that otherwise should mismatch. IDN hostnames are converted to puny code before used for certificate checks. Puny coded names always start with xn-- and should not be allowed to pattern match, but the wildcard check in curl could still check for x*, which would match even though the IDN name most likely contained nothing even resembling an x.

Weakness

The product does not validate, or incorrectly validates, a certificate.

Affected Software

Name	Vendor	Start Version	End Version
Curl	Haxx	*	8.1.0 (excluding)
JBoss Core Services for RHEL 8	RedHat	jbcs-httpd24-curl-0:8.2.1-1.el8jbcs	*
JBoss Core Services on RHEL 7	RedHat	jbcs-httpd24-curl-0:8.2.1-1.el7jbcs	*
Red Hat Enterprise Linux 8	RedHat	curl-0:7.61.1-30.el8_8.3	*
Red Hat Enterprise Linux 8.6 Extended Update Support	RedHat	curl-0:7.61.1-22.el8_6.9	*
Red Hat Enterprise Linux 9	RedHat	curl-0:7.76.1-23.el9_2.2	*
Red Hat Enterprise Linux 9	RedHat	curl-0:7.76.1-23.el9_2.2	*
Red Hat Enterprise Linux 9.0 Extended Update Support	RedHat	curl-0:7.76.1-14.el9_0.7	*
Text-Only JBCS	RedHat	jbcs-httpd24-curl	*
Curl	Ubuntu	bionic	*
Curl	Ubuntu	devel	*
Curl	Ubuntu	esm-infra-legacy/trusty	*
Curl	Ubuntu	esm-infra/bionic	*
Curl	Ubuntu	esm-infra/focal	*
Curl	Ubuntu	esm-infra/xenial	*
Curl	Ubuntu	focal	*
Curl	Ubuntu	jammy	*
Curl	Ubuntu	kinetic	*
Curl	Ubuntu	lunar	*
Curl	Ubuntu	mantic	*
Curl	Ubuntu	noble	*
Curl	Ubuntu	oracular	*
Curl	Ubuntu	plucky	*
Curl	Ubuntu	questing	*
Curl	Ubuntu	trusty	*
Curl	Ubuntu	trusty/esm	*
Curl	Ubuntu	upstream	*
Curl	Ubuntu	xenial	*

NVD	https://nvd.nist.gov/vuln/detail/CVE-2023-28321
CWE	https://cwe.mitre.org/data/definitions/295.html

Improper Certificate Validation

Weakness

Affected Software

Potential Mitigations

References

CVE-2023-28321

Improper Certificate Validation

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References