{"id":"CVE-2020-36477","aliases":["DEBIAN-CVE-2020-36477","EUVD-2020-23963","GHSA-qfcq-wvh3-6p75","JLSEC-2025-212","UBUNTU-CVE-2020-36477"],"status":"published","title":"An issue was discovered in Mbed TLS before 2.24.0. The verification of X.509 certificates when...","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).","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.00862,"percentile":0.58989,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-295"],"published":"2021-08-23T00:00:00Z","modified":"2026-10-26T12:02:02Z","fixes":[{"ecosystem":"Debian:12","package":"mbedtls","fixed_in":["2.28.0-0.3"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"mbedtls","fixed_in":["2.28.0-0.3"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"mbedtls","fixed_in":["2.28.0-0.3"],"sources":["osv"]},{"ecosystem":"Julia","package":"MbedTLS_jll","fixed_in":["2.24.0+0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.28.0-0.3"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.28.0-0.3"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.28.0-0.3"}]}]},{"source":"osv","ecosystem":"Julia","package":"MbedTLS_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.24.0+0"}]}]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.2-1","2.2.0-1","2.2.1-1","2.2.1-2","2.2.1-2ubuntu0.1","2.2.1-2ubuntu0.2","2.2.1-2ubuntu0.3"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.1-1ubuntu1","2.6.0-1","2.7.0-2","2.8.0-1","2.8.0-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"mbedtls","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.16.2-1","2.16.3-1","2.16.4-1ubuntu2","2.16.4-1ubuntu2+esm1"]}],"products":[{"vendor":"arm","product":"mbed_tls"}],"references":[{"url":"https://github.com/ARMmbed/mbedtls/releases/tag/v2.24.0","tags":["x_transferred","Release Notes","Third Party Advisory","advisory","web","report"]},{"url":"https://github.com/ARMmbed/mbedtls/issues/3498","tags":["x_transferred","Third Party Advisory","advisory","web","report"]},{"url":"https://security.gentoo.org/glsa/202301-08","tags":["vendor-advisory","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-36477"},{"url":"https://github.com/advisories/GHSA-qfcq-wvh3-6p75"},{"url":"https://security-tracker.debian.org/tracker/CVE-2020-36477","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2020-36477","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2020-36477","tags":["report"]}],"sources":{"cve":[{"id":"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).","status":"published","published":"2021-08-23T00:00:00Z","modified":"2024-08-04T17:30:08.378Z","updated_at":"2026-11-02T14:35:54.80237Z"}],"euvd":[{"id":"EUVD-2020-23963","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).","status":"published","published":"2021-08-23T00:00:00Z","modified":"2024-08-04T17:30:08Z","updated_at":"2026-11-03T03:07:03.010139Z"}],"ghsa":[{"id":"GHSA-qfcq-wvh3-6p75","title":"An issue was discovered in Mbed TLS before 2.24.0. The verification of X.509 certificates when...","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).","status":"published","published":"2022-05-24T19:11:58Z","modified":"2023-01-27T05:03:59Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:42:22.043841Z"}],"nvd":[{"id":"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).","status":"published","published":"2021-08-23T02:15:07.043Z","modified":"2026-06-17T03:15:34.56Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:06:45.704484Z"}],"osv":[{"id":"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).","status":"published","published":"2021-08-23T02:15:07.043Z","modified":"2026-10-20T10:53:26.407230531Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:16.936975Z"},{"id":"DEBIAN-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).","status":"published","published":"2021-08-23T02:15:07.043Z","modified":"2026-10-26T12:02:02.916643098Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:34.019707Z"},{"id":"JLSEC-2025-212","title":"An issue was discovered in Mbed TLS before 2.24.0","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).","status":"published","published":"2025-11-21T15:59:04.054Z","modified":"2026-07-23T22:30:19.640828485Z","cvss":[{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:47:17.805107Z"},{"id":"UBUNTU-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).","status":"published","published":"2021-08-23T02:15:00Z","modified":"2026-04-22T12:41:55.698464Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:54:25.179924Z"}]}}