CVE-2019-17023

nss: TLS 1.3 HelloRetryRequest downgrade request sets client into invalid state

Loading…

Severity

Low

Red Hat Product Security

5.3

CVSS 3.1

Review impact separately from score.

Published · January 8, 2020

Updated · June 27, 2026

Description

A protocol downgrade flaw was found in Network Security Services (NSS). After a HelloRetryRequest has been sent, the client may negotiate a lower protocol than 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.

Statement

This flaw causes the client to hang when there is a downgrade attempt. Therefore no actual protocol downgrade occurs.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 5.3
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

CWE not specified