Vulnerability · Published Aug 23, 2021 · Assigned by mitre
CVE-2020-36477
Medium 5.9
In plain English
A medium-severity security flaw in the mbedtls package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 59% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | mbedtls | 2.28.0-0.3 | DEBIAN-CVE-2020-36477 |
| Debian:13 | mbedtls | 2.28.0-0.3 | DEBIAN-CVE-2020-36477 |
| Debian:14 | mbedtls | 2.28.0-0.3 | DEBIAN-CVE-2020-36477 |