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 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.
Fix
Public exploits 3
- 0xxon/cve-2020-13777 PoC on GitHub
- prprhyt/PoC_TLS1_3_CVE-2020-13777 PoC on GitHub
- shigeki/challenge_CVE-2020-13777 PoC on GitHub
Each line links to the index that lists it, never to exploit code. Exploit-DB's "verified" and a Metasploit rank of good or better count as verified; a PoC-in-GitHub entry is a repository's claim.
Patch, vendor advisory and mitigation references on NVD 2
- https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03 Vendor Advisory
- https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03 Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.4 · gnu, fedoraproject, canonicalNVD modified 2026-10-14 10:17
Affected (CPE criteria) 6
cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
References 21
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00015.html Broken Link
- https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03 Vendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6C4DHUKV6M6SJ5CV6KVHZNHNF7HCUE5P/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6RTXZOXC4MHTFE2HKY6IAZMF2WHD2WMV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RRQBFK3UZ7SV76IYDTS4PS6ABS2DSJHK/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VMB3UGI5H5RCFRU6OGRPMNUCNLJGEN7Y/
- https://security.gentoo.org/glsa/202006-01 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20200619-0004/ Third Party Advisory
- https://usn.ubuntu.com/4384-1/ Third Party Advisory
- https://www.debian.org/security/2020/dsa-4697 Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00015.html Broken Link
- https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03 Vendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6C4DHUKV6M6SJ5CV6KVHZNHNF7HCUE5P/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6RTXZOXC4MHTFE2HKY6IAZMF2WHD2WMV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RRQBFK3UZ7SV76IYDTS4PS6ABS2DSJHK/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VMB3UGI5H5RCFRU6OGRPMNUCNLJGEN7Y/
- https://security.gentoo.org/glsa/202006-01 Third Party Advisory
- https://security.netapp.com/advisory/ntap-20200619-0004/ Third Party Advisory
- https://usn.ubuntu.com/4384-1/ Third Party Advisory
- https://www.debian.org/security/2020/dsa-4697 Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html