CVE-2020-36477

NameCVE-2020-36477
DescriptionAn 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).
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
mbedtls (PTS)stretch (security), stretch2.4.2-1+deb9u3vulnerable
buster2.16.0-1vulnerable
bookworm, sid, bullseye2.16.9-0.1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
mbedtlssource(unstable)(unfixed)

Notes

https://github.com/ARMmbed/mbedtls/issues/3498

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