| Name | CVE-2020-36477 |
| 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). |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| mbedtls (PTS) | stretch (security), stretch (lts), stretch | 2.4.2-1+deb9u4 | fixed |
| buster (security), buster, buster (lts) | 2.16.9-0~deb10u1 | fixed |
| bullseye | 2.16.9-0.1 | fixed |
| bookworm | 2.28.3-1 | fixed |
| trixie | 2.28.8-1 | fixed |
| sid | 3.6.2-3 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| mbedtls | source | experimental | 2.28.0-0.1 | | | |
| mbedtls | source | stretch | (not affected) | | | |
| mbedtls | source | buster | (not affected) | | | |
| mbedtls | source | bullseye | (not affected) | | | |
| mbedtls | source | (unstable) | 2.28.0-0.3 | | | |
Notes
[bullseye] - mbedtls <not-affected> (2.16 not affected)
[buster] - mbedtls <not-affected> (2.16 not affected)
[stretch] - mbedtls <not-affected> (2.4 not affected)
https://github.com/ARMmbed/mbedtls/issues/3498
https://github.com/ARMmbed/mbedtls/commit/f3e4bd8632b71dc491e52e6df87dc3e409d2b869 (development)