CVE-2020-26030

Name: CVE-2020-26030
Creator: NVD / NIST
Published: 2020-12-28T08:15:11.257+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.33%

Last modified Jun 17, 2026

CVE-2020-26030 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. An issue was discovered in Zammad before 3.4.1. There is an authentication bypass in the SSO endpoint via a crafted header, when SSO is not configured. EPSS estimates a 1.33% chance of exploitation in the next 30 days.

Description

An issue was discovered in Zammad before 3.4.1. There is an authentication bypass in the SSO endpoint via a crafted header, when SSO is not configured. An attacker can create a valid and authenticated session that can be used to perform any actions in the name of other users.

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

1.33%

67.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Zammad	Zammad	>= 1.0.0, < 3.4.1

References

https://zammad.com/news/security-advisory-zaa-2020-18Vendor Advisory
https://zammad.com/news/security-advisory-zaa-2020-18Vendor Advisory

Timeline

Published: Dec 28, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26030?

How severe is CVE-2020-26030?

CVE-2020-26030 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.33% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26030?

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-2020-26030?

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

Scan your code now

Source: NVD / NIST