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CVE-2026-93483

CVE-2026-93483

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 9.5 · Critical · EPSS 0.2% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • znuny

    Versions
    • ≥ 0, < 6.5.25: Affected (semver)
    • ≥ 7.0.0, < 7.3.7: Affected (semver)

    Update to 6.5.25; Update to 7.3.7

  • znuny Debian:12

    Versions
    • 6.3.2-3
    • 6.3.3-1
    • 6.3.3-1~bpo11+1
    • 6.3.4-1
    • 6.3.4-1~bpo11+1
    • 6.4.2-1
    • 6.4.2-1~bpo11+1
    • 6.4.2-2
    • 6.4.3-1
    • 6.4.3-1~bpo11+1
    • 6.4.4-1
    • 6.4.5-1
    • 6.4.5-1~bpo11+1
    • 6.4.5-2
    • 6.5.1-1
    • 6.5.10-1
    • 6.5.10-1~bpo12+1
    • 6.5.11-1
    • 6.5.11-1~bpo12+1
    • 6.5.13-1
    • 6.5.14-1
    • 6.5.14-1~bpo12+1
    • 6.5.15-1
    • 6.5.15-2
    • 6.5.15-2~bpo12+1
    • 6.5.16-1
    • 6.5.18-1
    • 6.5.18-1~bpo13+1
    • 6.5.19-1
    • 6.5.20-1
    • 6.5.21-1
    • 6.5.22-1
    • 6.5.22-1~bpo13+1
    • 6.5.23-1
    • 6.5.23-1~bpo13+1
    • 6.5.24-1
    • 6.5.24-1~bpo13+1
    • 6.5.25-1
    • 6.5.25-1~bpo13+1
    • 6.5.26-1
    • 6.5.26-1~bpo13+1
    • 6.5.3-1
    • 6.5.3-1~bpo12+1
    • 6.5.4-1
    • 6.5.4-1~bpo12+1
    • 6.5.5-1
    • 6.5.5-1~bpo12+1
    • 6.5.6-1
    • 6.5.6-1~bpo12+1
    • 6.5.8-1
    • 6.5.8-1~bpo12+1
    • 6.5.9-1
    • 6.5.9-1~bpo12+1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • znuny Debian:13

    Versions
    • 6.3.2-3
    • 6.3.3-1
    • 6.3.3-1~bpo11+1
    • 6.3.4-1
    • 6.3.4-1~bpo11+1
    • 6.4.2-1
    • 6.4.2-1~bpo11+1
    • 6.4.2-2
    • 6.4.3-1
    • 6.4.3-1~bpo11+1
    • 6.4.4-1
    • 6.4.5-1
    • 6.4.5-1~bpo11+1
    • 6.4.5-2
    • 6.5.1-1
    • 6.5.10-1
    • 6.5.10-1~bpo12+1
    • 6.5.11-1
    • 6.5.11-1~bpo12+1
    • 6.5.13-1
    • 6.5.14-1
    • 6.5.14-1~bpo12+1
    • 6.5.15-1
    • 6.5.15-2
    • 6.5.15-2~bpo12+1
    • 6.5.16-1
    • 6.5.18-1
    • 6.5.18-1~bpo13+1
    • 6.5.19-1
    • 6.5.20-1
    • 6.5.21-1
    • 6.5.22-1
    • 6.5.22-1~bpo13+1
    • 6.5.23-1
    • 6.5.23-1~bpo13+1
    • 6.5.24-1
    • 6.5.24-1~bpo13+1
    • 6.5.25-1
    • 6.5.25-1~bpo13+1
    • 6.5.26-1
    • 6.5.26-1~bpo13+1
    • 6.5.3-1
    • 6.5.3-1~bpo12+1
    • 6.5.4-1
    • 6.5.4-1~bpo12+1
    • 6.5.5-1
    • 6.5.5-1~bpo12+1
    • 6.5.6-1
    • 6.5.6-1~bpo12+1
    • 6.5.8-1
    • 6.5.8-1~bpo12+1
    • 6.5.9-1
    • 6.5.9-1~bpo12+1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • znuny Debian:14

    Versions
    • 6.3.2-3
    • 6.3.3-1
    • 6.3.3-1~bpo11+1
    • 6.3.4-1
    • 6.3.4-1~bpo11+1
    • 6.4.2-1
    • 6.4.2-1~bpo11+1
    • 6.4.2-2
    • 6.4.3-1
    • 6.4.3-1~bpo11+1
    • 6.4.4-1
    • 6.4.5-1
    • 6.4.5-1~bpo11+1
    • 6.4.5-2
    • 6.5.1-1
    • 6.5.10-1
    • 6.5.10-1~bpo12+1
    • 6.5.11-1
    • 6.5.11-1~bpo12+1
    • 6.5.13-1
    • 6.5.14-1
    • 6.5.14-1~bpo12+1
    • 6.5.15-1
    • 6.5.15-2
    • 6.5.15-2~bpo12+1
    • 6.5.16-1
    • 6.5.18-1
    • 6.5.18-1~bpo13+1
    • 6.5.19-1
    • 6.5.20-1
    • 6.5.21-1
    • 6.5.22-1
    • 6.5.22-1~bpo13+1
    • 6.5.23-1
    • 6.5.23-1~bpo13+1
    • 6.5.24-1
    • 6.5.24-1~bpo13+1
    • 6.5.25-1~bpo13+1
    • 6.5.3-1
    • 6.5.3-1~bpo12+1
    • 6.5.4-1
    • 6.5.4-1~bpo12+1
    • 6.5.5-1
    • 6.5.5-1~bpo12+1
    • 6.5.6-1
    • 6.5.6-1~bpo12+1
    • 6.5.8-1
    • 6.5.8-1~bpo12+1
    • 6.5.9-1
    • 6.5.9-1~bpo12+1
    Affected ranges
    • ECOSYSTEM: < 6.5.25-1

    Update to 6.5.25-1

  • otrs2 Ubuntu:16.04:LTS

    Versions
    • 4.0.10-1
    • 5.0.1-1
    • 5.0.1-2
    • 5.0.2-1
    • 5.0.3-1
    • 5.0.5-1
    • 5.0.6-1
    • 5.0.7-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • otrs2 Ubuntu:18.04:LTS

    Versions
    • 5.0.23-1
    • 5.0.24-1
    • 6.0.1-1
    • 6.0.2-1
    • 6.0.3-1
    • 6.0.4-1
    • 6.0.5-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • otrs2 Ubuntu:20.04:LTS

    Versions
    • 6.0.20-1
    • 6.0.23-2
    • 6.0.24-1
    • 6.0.25-1
    • 6.0.25-2
    • 6.0.25-3
    • 6.0.26-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • otrs2 Ubuntu:22.04:LTS

    Versions
    • 6.0.32-6
    • 6.1.2-1
    • 6.2.1-1
    • 6.2.2-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • znuny Ubuntu:24.04:LTS

    Versions
    • 6.5.3-1
    • 6.5.4-1
    • 6.5.5-1
    • 6.5.6-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • znuny Ubuntu:26.10

    Versions
    • 6.5.18-1
    • 6.5.20-1
    • 6.5.21-1
    • 6.5.22-1
    • 6.5.23-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • znuny Ubuntu:26.04:LTS

    Versions
    • 6.5.15-2
    • 6.5.18-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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