Linux systems are often trusted for their strong security model—but that trust can be undermined when privileged system utilities expose flawed authentication logic. In January 2026, security researchers from SUSE disclosed a critical Linux vulnerability in TLP, a widely used battery and power‑management utility.
Tracked as CVE‑2025‑67859, the flaw allows local attackers to bypass Polkit authentication, manipulate system power profiles, and tamper with daemon behavior without administrator privileges.
For Linux administrators and security teams, this vulnerability highlights a growing risk area: D‑Bus–enabled system services interacting with deprecated authorization mechanisms. In this article, we break down what went wrong, why it matters, how attackers could exploit it, and what organizations must do immediately.
What Is TLP and Why Is It Widely Used?
TLP (The Laptop Power Management utility) is a popular Linux tool designed to improve battery life on laptops by dynamically adjusting power‑related system settings.
Common Use Cases for TLP
- Laptop battery optimization
- Power profile switching (AC vs battery)
- Performance tuning for mobile Linux systems
- Enterprise Linux workstation management
Because TLP directly interfaces with kernel‑level and hardware power settings, it operates with elevated privileges—making any authentication flaw particularly dangerous.
Overview of CVE‑2025‑67859
| Attribute | Details |
|---|---|
| CVE ID | CVE‑2025‑67859 |
| Vulnerability Type | Polkit Authentication Bypass |
| Severity | Critical |
| Affected Version | TLP 1.9.0 |
| Fixed Version | TLP 1.9.1+ |
| Attack Vector | Local (Privilege Abuse) |
This vulnerability was uncovered during a comprehensive security audit conducted by SUSE researchers Matthias Gerstner and Filippo Bonazzi.
The Core Vulnerability Explained
Root Cause: Unsafe Polkit Authorization
The critical flaw lies in how TLP 1.9.0 implements Polkit authentication for its newly introduced power daemon, which exposes a D‑Bus API for controlling system power parameters.
Instead of using modern authorization methods, the daemon relied on Polkit’s deprecated:
“unix‑process” subject
This subject type makes authorization decisions based on process IDs (PIDs)—a design known to be vulnerable to race condition attacks.
How the Authentication Bypass Works
- A local user initiates a privileged D‑Bus request
- Polkit checks authorization using the process ID
- During the authentication window, the attacker replaces the process
- Polkit mistakenly authorizes a different, higher‑privilege process
✅ Result: Unauthorized access to privileged power‑management actions
This allows attackers to:
- Modify system power profiles
- Change daemon logging behavior
- Interfere with system stability and performance
⚠️ No admin credentials required
Additional Security Issues Identified
Beyond CVE‑2025‑67859, SUSE researchers uncovered three more weaknesses that further expanded the attack surface.
1. Predictable Cookie Values
- Enables unauthorized users to release profile holds
- Weak entropy undermines access controls
2. Unhandled Exceptions
- Malformed D‑Bus requests trigger daemon errors
- Potential crash or unexpected behavior
3. Unlimited Profile Holds (DoS Risk)
- Attackers can exhaust resources
- Results in denial‑of‑service conditions
While these flaws are lower severity individually, their combination materially increases exploitation risk.
Real‑World Attack Scenarios
Scenario 1: Insider Threat or Shared System Abuse
On shared Linux environments (labs, universities, enterprises), any local user could:
- Interfere with system power settings
- Degrade performance or availability
- Bypass administrative intent
Scenario 2: Post‑Exploitation Privilege Abuse
After gaining initial access through another vulnerability:
- Attackers can use TLP to persist
- Alter system behavior stealthily
- Evade monitoring by manipulating logging levels
Coordinated Disclosure and Responsible Fix
SUSE initiated responsible disclosure on December 16, 2025, contacting the upstream TLP developer.
Fix Timeline
- December 16, 2025: Developer notified
- Within 4 days: Initial patch shared
- January 7, 2026: TLP 1.9.1 released
This rapid response demonstrates effective coordinated vulnerability disclosure.
Security Fixes Implemented in TLP 1.9.1
The updated release introduced multiple hardening measures:
✅ Switched from unix‑process to secure system‑bus‑name Polkit subject
✅ Generated unpredictable cookie values
✅ Limited profile holds to 16 concurrent instances
✅ Improved exception handling for malformed requests
These changes significantly reduce exploitation risk.
Why This Vulnerability Matters for Linux Security
This incident underscores several broader security lessons:
1. D‑Bus APIs Are High‑Risk Interfaces
Services that expose system controls must be hardened by design.
2. Deprecated Security Mechanisms Are Dangerous
Legacy authorization models increase exploitation likelihood.
3. Local Vulnerabilities Still Matter
Privilege abuse and insider threats remain high‑impact attack vectors.
Best Practices for Linux Administrators
Immediate Actions
- ✅ Upgrade to TLP 1.9.1 or later immediately
- ✅ Verify installed versions across all systems
- ✅ Restart the TLP daemon after patching
Enterprise Security Recommendations
- Enforce package version compliance
- Audit D‑Bus services running as root
- Review all Polkit policies for deprecated subjects
- Include local privilege abuse in threat modeling
Compliance and Security Framework Alignment
This vulnerability is relevant to:
- CIS Benchmark for Linux – Privileged service hardening
- NIST SP 800‑53 – AC, IA, and CM controls
- ISO/IEC 27001 – Secure system operation
- SOC 2 – Logical access controls
Ignoring such flaws can weaken compliance posture.
FAQs: Linux TLP Vulnerability CVE‑2025‑67859
What is CVE‑2025‑67859?
A critical Polkit authentication bypass vulnerability in TLP 1.9.0 allowing unauthorized system power control.
Is remote exploitation possible?
No. This is a local vulnerability, but impact is still severe.
Which versions are affected?
Only TLP 1.9.0 is affected. Version 1.9.1+ is safe.
What is the recommended remediation?
Update immediately via your Linux distribution’s package manager.
Why is this considered critical?
It allows privilege bypass on a tool that controls system‑level operations.
Conclusion: Privileged Utilities Demand Extra Scrutiny
The Linux TLP vulnerability CVE‑2025‑67859 serves as a reminder that system utilities are part of the attack surface—especially those communicating over D‑Bus with elevated privileges.
Admins and security teams should:
- Patch immediately
- Audit privileged daemons
- Eliminate deprecated authentication patterns
Security audits catch what attackers eventually exploit. Prevention always wins.
