CVE-2026-93483

In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable "Remote-User" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials.

CVSS

No CVSS.

References

Link	Resource
https://www.znuny.org/advisories
https://www.znuny.org/en/advisories/zsa-2026-14

Configurations

No configuration.

History

15 Oct 2026, 04:18

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-15 04:18

Updated : 2026-10-19 19:18

NVD link : CVE-2026-93483

Mitre link : CVE-2026-93483

CVE.ORG link : CVE-2026-93483

JSON object : View

Products Affected

No product.

CWE

CWE-348

Use of Less Trusted Source

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