CVE-2026-12250: Pardus Domain Joiner Info Disclosure Flaw

CVE-2026-12250 Overview

CVE-2026-12250 is an information exposure vulnerability affecting the Pardus Domain Joiner, developed by TUBITAK BILGEM Software Technologies Research Institute. The flaw is classified under [CWE-214] (Invocation of Process Using Visible Sensitive Information). Pardus Domain Joiner passes sensitive parameters on the command line during process invocation, exposing them to other local users through standard process inspection interfaces. The issue affects Pardus Domain Joiner versions from 0.5.2 before 0.5.4. An authenticated local attacker can harvest these values to compromise domain-joining credentials or related secrets.

Critical Impact
Local users on a Pardus workstation can read sensitive command-line arguments — including domain-joining credentials — from process listings, leading to confidentiality and integrity impact on domain identity infrastructure.

Affected Products

TUBITAK BILGEM Pardus Domain Joiner 0.5.2
TUBITAK BILGEM Pardus Domain Joiner versions after 0.5.2 and before 0.5.4
Pardus Linux systems using Domain Joiner for Active Directory or LDAP enrollment

Discovery Timeline

2026-07-05 - CVE-2026-12250 published to NVD
2026-07-06 - Last updated in NVD database

Technical Details for CVE-2026-12250

Vulnerability Analysis

Pardus Domain Joiner automates the process of joining a Linux workstation to a Windows or Samba domain. To perform the join, it invokes external helper processes such as realm, net, or adcli. The vulnerability arises because sensitive arguments — including domain administrator usernames and passwords — are passed directly on the command line when spawning these child processes.

On Linux systems, command-line arguments are readable by any local user through the /proc/<pid>/cmdline pseudo-file and standard tools such as ps, top, and htop. Any user with a local shell session during the domain-join operation can observe the secret in cleartext. The exposure window covers the entire lifetime of the helper process.

The vulnerability requires local access and user interaction to trigger the join workflow, but the scope is changed because the leaked credentials typically grant privileged access to the domain controller — an authority beyond the vulnerable component.

Root Cause

The root cause is unsafe process invocation. Instead of supplying credentials through environment variables, standard input, an anonymous pipe, or a keyring, the Domain Joiner concatenates them into the argument vector (argv). Linux does not restrict read access to /proc/<pid>/cmdline by default, so any local user can enumerate the arguments.

Attack Vector

A logged-in local user monitors process activity while an administrator initiates a domain-join operation. The attacker runs a polling loop against ps auxww or /proc/*/cmdline to capture the credentials from the running adcli or net ads join process. No elevated privileges are required to read the arguments. The attacker then reuses the captured domain credentials to authenticate against the domain controller, escalating impact beyond the local host.

The vulnerability manifests during the invocation of the join helper process. Refer to the Siber Güvenlik Notification TR-26-0498 for the authoritative vendor description.

Detection Methods for CVE-2026-12250

Indicators of Compromise

Execution of ps, top, htop, pgrep, or repeated reads of /proc/*/cmdline by non-administrative users coinciding with domain-join activity.
Presence of adcli join, net ads join, or realm join invocations with plaintext password arguments in shell history or audit logs.
Unexpected authentications to the domain controller originating from workstations that recently ran the Domain Joiner.

Detection Strategies

Enable Linux Audit (auditd) rules on execve to log full command lines and flag helper processes invoked with credential-bearing arguments.
Correlate Pardus Domain Joiner execution events with subsequent /proc traversal by unrelated user sessions on the same host.
Alert on domain controller authentication events from service accounts shortly after workstation join operations from unexpected source IPs.

Monitoring Recommendations

Ingest auditd and /var/log/auth.log telemetry into a centralized SIEM to reconstruct join workflows and identify credential exposure windows.
Monitor for the installed version of the pardus-domain-joiner package across the fleet and flag hosts running versions below 0.5.4.
Watch for shell activity that reads /proc/<pid>/cmdline outside of standard system administration tooling.

How to Mitigate CVE-2026-12250

Immediate Actions Required

Upgrade Pardus Domain Joiner to version 0.5.4 or later on all affected Pardus workstations.
Rotate any domain-join or administrative credentials that were used with vulnerable versions, assuming exposure.
Restrict interactive local access on workstations that perform domain-join operations to trusted administrators only.

Patch Information

The issue is resolved in Pardus Domain Joiner version 0.5.4. Administrators should deploy the fixed package through the Pardus package repositories. Refer to the Siber Güvenlik Notification TR-26-0498 for vendor guidance.

Workarounds

Perform domain-join operations only on freshly provisioned hosts with no other logged-in users.
Use a dedicated, low-privilege domain-join account with permissions limited to computer object creation, and rotate the password immediately after each join.
Where feasible, mount /proc with the hidepid=2 option so users can only see their own process command lines: mount -o remount,hidepid=2 /proc.

bash

# Configuration example: harden /proc to hide other users' command lines
# Add to /etc/fstab
proc  /proc  proc  defaults,hidepid=2,gid=proc  0  0

# Apply immediately without reboot
sudo mount -o remount,hidepid=2 /proc

# Verify the current Pardus Domain Joiner version
dpkg -s pardus-domain-joiner | grep '^Version:'

# Upgrade to the fixed release
sudo apt update && sudo apt install --only-upgrade pardus-domain-joiner