CVE-2020-13777

Publication date 4 June 2020

Last updated 25 August 2025

Ubuntu priority

High

Why this priority?

Cvss 3 Severity Score

7.4 · High

Score breakdown

Description

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
gnutls28 20.04 LTS focal
Fixed 3.6.13-2ubuntu1.1
19.10 eoan
Fixed 3.6.9-5ubuntu1.2
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release

Notes

mdeslaur

introduced in 3.6.4

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
gnutls28

Severity score breakdown

Parameter Value
Base score 7.4 · High
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact None
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Related Ubuntu Security Notices (USN)

Other references