{"id":"CVE-2020-13777","title":"GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3)","summary":"GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). The earliest affected version is 3.6.4 (2018-09-24) because of an err…","severity":"high","cvss":7.4,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-327"],"vendor":"gnu","product":"gnutls","affected":["gnutls >= 3.6.0, < 3.6.14","fedora = 31","fedora = 32","ubuntu_linux = 19.10","ubuntu_linux = 20.04","debian_linux = 10.0"],"patched":["gnutls 3.6.14"],"published":"2020-06-04","updated":"2026-10-14","sourceUpdated":"2026-10-14T10:17:29.130","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-13777","references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00015.html","label":"cve@mitre.org"},{"url":"https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6C4DHUKV6M6SJ5CV6KVHZNHNF7HCUE5P/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6RTXZOXC4MHTFE2HKY6IAZMF2WHD2WMV/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RRQBFK3UZ7SV76IYDTS4PS6ABS2DSJHK/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VMB3UGI5H5RCFRU6OGRPMNUCNLJGEN7Y/","label":"cve@mitre.org"},{"url":"https://security.gentoo.org/glsa/202006-01","label":"cve@mitre.org"},{"url":"https://security.netapp.com/advisory/ntap-20200619-0004/","label":"cve@mitre.org"},{"url":"https://usn.ubuntu.com/4384-1/","label":"cve@mitre.org"},{"url":"https://www.debian.org/security/2020/dsa-4697","label":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00015.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6C4DHUKV6M6SJ5CV6KVHZNHNF7HCUE5P/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6RTXZOXC4MHTFE2HKY6IAZMF2WHD2WMV/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RRQBFK3UZ7SV76IYDTS4PS6ABS2DSJHK/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VMB3UGI5H5RCFRU6OGRPMNUCNLJGEN7Y/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202006-01","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20200619-0004/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4384-1/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2020/dsa-4697","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","exploit-available","cve.org"],"epss":0.22284,"epssPercentile":0.97641,"exploits":{"github":3,"githubRepos":["https://github.com/0xxon/cve-2020-13777","https://github.com/shigeki/challenge_CVE-2020-13777","https://github.com/prprhyt/PoC_TLS1_3_CVE-2020-13777"],"checkedAt":"2026-10-14T10:26:15.308Z"},"exploitAvailable":true,"ingestedAt":"2026-10-14T10:25:41.176Z","slug":"CVE-2020-13777","body":"## Overview\n\nGnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). The earliest affected version is 3.6.4 (2018-09-24) because of an error in a 2018-09-18 commit. Until the first key rotation, the TLS server always uses wrong data in place of an encryption key derived from an application.\n\n## Affected\n\n- `gnutls >= 3.6.0, < 3.6.14`\n- `fedora = 31`\n- `fedora = 32`\n- `ubuntu_linux = 19.10`\n- `ubuntu_linux = 20.04`\n- `debian_linux = 10.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `gnutls 3.6.14`","depth":"midnight","depthScore":57,"depthScoreParts":{"impact":40.7,"likelihood":4.5,"exploitation":12,"ransomware":0},"changes":[]}