CVE-2026-93483 (GCVE-0-2026-93483)

Vulnerability from cvelistv5 – Published: 2026-10-15 03:43 – Updated: 2026-10-15 03:43
VLAI
Summary
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.
Severity
9.5 (Critical)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/AU:Y/R:U/RE:L/U:Red
CWE
  • CWE-348 - Use of Less Trusted Source
Assigner
mitre CNA under the mitre root
CNA scorecard E 28/100 over 2325 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Znuny Znuny Affected: 0 , < 6.5.25 (semver)
Affected: 7.0.0 , < 7.3.7 (semver)
    cpe:2.3:a:znuny:znuny:*:*:*:*:*:*:*:*
    cpe:2.3:a:znuny:znuny:*:*:*:*:*:*:*:*
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