Medium severity · published Apr 8, 2026
CVE-2026-34720
Zammad has an origin validation error in SSO mechanism
4.3
CVSS
0.1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZA
zammad · zammad
< 6.5.4; >= 7.0.0-alpha, < 7.0.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34720
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34720
Vendor Advisory
https://github.com/zammad/zammad/security/advisories/GHSA-hcv6-w4h9-p2p7
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