An issue was discovered in Mbed TLS before 2.24.0. The verification of X.509 certificates when matching the expected common name (the cn argument of mbedtls_x509_crt_verify) with the actual certificate name is mishandled: when the subjecAltName extension is present, the expected name is compared to any name in that extension regardless of its type. This means that an attacker could impersonate a 4-byte or 16-byte domain by getting a certificate for the corresponding IPv4 or IPv6 address (this would require the attacker to control that IP address, though).
Advisories
Source ID Title
EUVD EUVD EUVD-2020-23963 An issue was discovered in Mbed TLS before 2.24.0. The verification of X.509 certificates when matching the expected common name (the cn argument of mbedtls_x509_crt_verify) with the actual certificate name is mishandled: when the subjecAltName extension is present, the expected name is compared to any name in that extension regardless of its type. This means that an attacker could impersonate a 4-byte or 16-byte domain by getting a certificate for the corresponding IPv4 or IPv6 address (this would require the attacker to control that IP address, though).
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

No history.

cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2024-08-04T17:30:08.378Z

Reserved: 2021-08-23T00:00:00

Link: CVE-2020-36477

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-08-23T02:15:07.043

Modified: 2024-11-21T05:29:38.067

Link: CVE-2020-36477

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.