CVE-2019-17023

Publication date 8 January 2020

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

After a HelloRetryRequest has been sent, the client may negotiate a lower protocol that TLS 1.3, resulting in an invalid state transition in the TLS State Machine. If the client gets into this state, incoming Application Data records will be ignored. This vulnerability affects Firefox < 72.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
firefox	20.04 LTS focal	Fixed 72.0.1+build1-0ubuntu1
	19.10 eoan	Fixed 72.0.1+build1-0ubuntu0.19.10.1
	19.04 disco	Fixed 72.0.1+build1-0ubuntu0.19.04.1
	18.04 LTS bionic	Fixed 72.0.1+build1-0ubuntu0.18.04.1
	16.04 LTS xenial	Fixed 72.0.1+build1-0ubuntu0.16.04.1
	14.04 LTS trusty	Not in release
nss	20.04 LTS focal	Not affected
	19.10 eoan	Fixed 2:3.45-1ubuntu2.3
	19.04 disco	Ignored end of life
	18.04 LTS bionic	Fixed 2:3.35-2ubuntu2.8
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

mdeslaur

nss in xenial is built with NSS_DISABLE_TLS_1_3, so this issue doesn't affect it.

Patch details

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

Package	Patch details
nss	Upstream: https://hg.mozilla.org/projects/nss/rev/d64102b76a437f24d98a20480dcc9f1655143e7c Upstream: https://hg.mozilla.org/projects/nss/rev/8a2bd40e7f89a796cf24a0ff7cfb67c6e69c5c78

Severity score breakdown

Parameter	Value
Base score	6.5 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N