CVE-2022-23959

Name: CVE-2022-23959
Creator: NVD / NIST
Published: 2022-01-26T01:15:07.9+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 1.96%

Last modified Jun 17, 2026

CVE-2022-23959 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. In Varnish Cache before 6.6.2 and 7.x before 7.0.2, Varnish Cache 6.0 LTS before 6.0.10, and and Varnish Enterprise (Cache Plus) 4.1.x before 4.1.11r6 and 6.0.x before 6.0.9r4, request smuggling can occur for HTTP/1 connections.. EPSS estimates a 1.96% chance of exploitation in the next 30 days.

Description

In Varnish Cache before 6.6.2 and 7.x before 7.0.2, Varnish Cache 6.0 LTS before 6.0.10, and and Varnish Enterprise (Cache Plus) 4.1.x before 4.1.11r6 and 6.0.x before 6.0.9r4, request smuggling can occur for HTTP/1 connections.

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

1.96%

77.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-444

Affected Software

Vendor	Product	Versions
Varnish-Software	Varnich Cache	>= 1.0.0, < 6.6.2
Varnish-Software	Varnich Cache	>= 4.1.1, < 4.1.11r6
Varnish-Software	Varnich Cache	4.1
Varnish-Software	Varnish Cache	>= 6.0.0, < 6.0.10
Varnish-Software	Varnish Cache Plus	>= 6.0.0, < 6.0.9r4
Varnish Cache Project	Varnish Cache	>= 7.0.0, < 7.0.2
Fedoraproject	Fedora	35
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0

References

https://docs.varnish-software.com/security/VSV00008/Mitigation, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2022/02/msg00014.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UMMDMQWNAE3BTSZUHXQHVAMZC5TLHLYT/
https://varnish-cache.org/security/VSV00008.htmlMitigation, Vendor Advisory
https://www.debian.org/security/2022/dsa-5088Third Party Advisory
https://docs.varnish-software.com/security/VSV00008/Mitigation, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2022/02/msg00014.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UMMDMQWNAE3BTSZUHXQHVAMZC5TLHLYT/
https://varnish-cache.org/security/VSV00008.htmlMitigation, Vendor Advisory
https://www.debian.org/security/2022/dsa-5088Third Party Advisory

Timeline

Published: Jan 26, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-23959?

How severe is CVE-2022-23959?

CVE-2022-23959 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 1.96% probability of exploitation in the next 30 days.

How do I fix CVE-2022-23959?

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-2022-23959?

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

Scan your code now

Source: NVD / NIST