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...
- Published
- Jun 4, 2020
- Updated
- Oct 14, 2026
- Assigning CNA
- mitre
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NModerate · next 30 days
- Percentile
- 97.7%
- Model date
- Oct 18, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
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 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.
Sources
- cve-2020-13777Detection
Zeek script to detect servers vulnerable to CVE-2020-13777
- challenge_CVE-2020-13777Research
Challange CVE-2020-13777
Proof-of-concept for CVE-2020-13777 (GnuTLS TLS 1.3 reconnect vulnerability). Parses pcap files to demonstrate the flaw for educational and technical verification purposes.
Responsible use
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