CVE-2020-13777

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.

CVSS 3.1

7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

22% chance of exploitation in the next 30 days; higher than 97% of CVEs (scores of 2026-10-25)

CWE

CWE-327

Published

2020-06-04

Modified

2026-10-14

Record from

the NVD, synced 2026-10-19

Affected

• canonical:ubuntu_linux
• debian:debian_linux
• fedoraproject:fedora
• gnu:gnutls

References

• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00015.html
• https://gnutls.org/security-new.html#GNUTLS-SA-2020-06-03
• 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/

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