CVE-2019-17023

Name: CVE-2019-17023
Creator: NVD / NIST
Published: 2020-01-08T22:15:12.827+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.34%

Last modified Jun 17, 2026

CVE-2019-17023 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 1.34% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.34%

67.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 72.0
Canonical	Ubuntu Linux	16.04
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	19.04
Canonical	Ubuntu Linux	19.10
Canonical	Ubuntu Linux	20.04
Debian	Debian Linux	10.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1590001Issue Tracking, Permissions Required
https://usn.ubuntu.com/4234-1/Third Party Advisory
https://usn.ubuntu.com/4397-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4726Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-01/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1590001Issue Tracking, Permissions Required
https://usn.ubuntu.com/4234-1/Third Party Advisory
https://usn.ubuntu.com/4397-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4726Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-01/Vendor Advisory

Timeline

Published: Jan 8, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-17023?

How severe is CVE-2019-17023?

CVE-2019-17023 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.34% probability of exploitation in the next 30 days.

How do I fix CVE-2019-17023?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-17023?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST