What is CVE-2026-34720?

CVE-2026-34720 is a medium-severity vulnerability in Zammad, classified under Origin Validation Error. CVSS score: 4.3/10. Published 2026-04-08.

How severe is CVE-2026-34720?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Zammad

CVE-2026-34720

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the SSO mechanism in Zammad was not verifying the header originates from a trusted SSO proxy/gateway before applying further actions on it. This vulnerability is fixed in 7.0.1 and 6.5.4.

EPSS: 0.001 (1.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

Affected products

Zammad — versions < 6.5.4, 7.0.0, >= 7.0.0-alpha, < 7.0.1

Weakness classification (CWE)

CWE-346 — Origin Validation Error

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-34720?: CVE-2026-34720 is a medium-severity vulnerability in Zammad, classified under Origin Validation Error. CVSS score: 4.3/10. Published 2026-04-08.
How severe is CVE-2026-34720?: Medium severity. CVSS v3 base score is 4.3 out of 10.