Vulnerability in Zammad Helpdesk Software Exposes Internal Network
CVE-2026-56734

5.3MEDIUM

Key Information:

Vendor

Zammad

Status
Zammad
Vendor
CVE Published:
25 September 2026

What is CVE-2026-56734?

Zammad, an open-source helpdesk/customer support system, has a vulnerability related to federated authentication methods such as OAuth, OIDC, and SAML. In versions prior to 7.0.2, the application retrieves a profile image URL from an external identity provider without validating the target address. This flaw can be exploited by an actor who can modify their profile image URL on the connected provider, potentially leading the server to connect to internal network locations. The differential response patterns between reachable and unreachable targets may allow attackers to probe internal services. Additionally, affected worker processes could experience blocking for several seconds per request. This issue was resolved in version 7.0.2.

Affected Version(s)

zammad < 7.0.2

References

https://github.com/zammad/zammad/security/advisories/GHSA...
x_refsource_CONFIRM
https://github.com/zammad/zammad/commit/1fae97d92496a643e...
x_refsource_MISC
https://github.com/zammad/zammad/releases/tag/7.0.2
x_refsource_MISC

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.