CVE-2021-37592

Name: CVE-2021-37592
Creator: NVD / NIST
Published: 2021-11-19T15:15:08.137+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.55%

Last modified Jun 17, 2026

CVE-2021-37592 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Suricata before 5.0.8 and 6.x before 6.0.4 allows TCP evasion via a client with a crafted TCP/IP stack that can send a certain sequence of segments.. EPSS estimates a 1.55% chance of exploitation in the next 30 days.

Description

Suricata before 5.0.8 and 6.x before 6.0.4 allows TCP evasion via a client with a crafted TCP/IP stack that can send a certain sequence of segments.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.55%

72.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Oisf	Suricata	< 5.0.8
Oisf	Suricata	>= 6.0.0, < 6.0.4

References

https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942Release Notes, Vendor Advisory
https://github.com/OISF/suricata/releasesRelease Notes, Third Party Advisory
https://redmine.openinfosecfoundation.org/issues/4569Permissions Required, Third Party Advisory
https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942Release Notes, Vendor Advisory
https://github.com/OISF/suricata/releasesRelease Notes, Third Party Advisory
https://redmine.openinfosecfoundation.org/issues/4569Permissions Required, Third Party Advisory

Timeline

Published: Nov 19, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-37592?

Suricata before 5.0.8 and 6.x before 6.0.4 allows TCP evasion via a client with a crafted TCP/IP stack that can send a certain sequence of segments.

How severe is CVE-2021-37592?

CVE-2021-37592 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.55% probability of exploitation in the next 30 days.

How do I fix CVE-2021-37592?

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-2021-37592?

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

Scan your code now

Source: NVD / NIST