CVE-2026-11765 Overview
CVE-2026-11765 is an argument injection vulnerability in Pardus Pen, a screen annotation tool developed by TUBITAK BILGEM Software Technologies Research Institute. The flaw exists in versions before 4.2.1 and is classified under [CWE-88] Improper Neutralization of Argument Delimiters in a Command. A local authenticated attacker can supply crafted input that is passed unsanitized as arguments to a downstream command. The condition allows limited tampering with integrity but does not expose confidential data or degrade availability.
Critical Impact
A local, low-privileged attacker can inject additional command-line arguments to alter the behavior of a spawned process, resulting in limited integrity impact on the affected system.
Affected Products
- TUBITAK BILGEM Pardus Pen versions prior to 4.2.1
- Linux systems running Pardus Pen as a local application
- Deployments using the vulnerable command-invocation path in Pardus Pen
Discovery Timeline
- 2026-09-11 - CVE-2026-11765 published to the National Vulnerability Database (NVD)
- 2026-09-11 - Last updated in NVD database
Technical Details for CVE-2026-11765
Vulnerability Analysis
The vulnerability arises when Pardus Pen constructs a command line using attacker-influenced input without properly neutralizing argument delimiters such as leading dashes or option separators. When the constructed command is executed, the injected tokens are interpreted by the target program as legitimate options or flags rather than as data. This changes the intended behavior of the invoked process.
Exploitation requires local access and low privileges on the host. No user interaction is required beyond the attacker's own actions. The impact is bounded to limited integrity effects; the vulnerability does not disclose sensitive data and does not directly cause a denial of service.
Because the flaw is local and requires an authenticated session, its practical reach is narrow. The EPSS forecast indicates a low probability of near-term exploitation in the wild, and no public exploit or proof-of-concept has been referenced.
Root Cause
The root cause is missing or incomplete sanitization of user-controlled input that becomes part of a subprocess invocation. Argument delimiters embedded in the input are passed verbatim to the executed program, allowing the attacker to introduce new arguments. This class of defect is tracked by [CWE-88].
Attack Vector
An attacker with local access to a system running a vulnerable Pardus Pen version supplies input containing argument delimiters. Pardus Pen forwards that input to a spawned process. The child process interprets the injected tokens as switches, altering execution parameters chosen by the developer.
No verified proof-of-concept has been published. See the Siber Güvenlik Notification TR-26-1079 for the vendor-coordinated advisory.
Detection Methods for CVE-2026-11765
Indicators of Compromise
- Pardus Pen child processes launched with unexpected command-line flags not present in the default configuration
- Application logs showing user-supplied strings that contain --, -, or option-like tokens forwarded to subprocesses
- Modifications to files or settings outside the scope of normal Pardus Pen annotation workflows
Detection Strategies
- Enable process-creation auditing on Linux endpoints and inspect the full command line of processes spawned by Pardus Pen
- Build allowlists of expected argument patterns for Pardus Pen child processes and alert on deviations
- Correlate local user session activity with unusual Pardus Pen invocations to identify potential abuse
Monitoring Recommendations
- Forward execve telemetry from Linux hosts into a centralized analytics or SIEM platform for retrospective review
- Monitor installed Pardus Pen versions across the fleet and flag hosts running versions earlier than 4.2.1
- Track file integrity for artifacts that Pardus Pen or its child processes are permitted to write
How to Mitigate CVE-2026-11765
Immediate Actions Required
- Upgrade Pardus Pen to version 4.2.1 or later on all affected systems
- Inventory endpoints running Pardus Pen and prioritize multi-user hosts for patching
- Restrict interactive local access on systems that cannot be updated immediately
Patch Information
The vendor addressed the vulnerability in Pardus Pen version 4.2.1. Refer to the Siber Güvenlik Notification TR-26-1079 for the official remediation guidance issued by TUBITAK BILGEM.
Workarounds
- Limit Pardus Pen usage to trusted local users until the patched version is deployed
- Apply operating system access controls to prevent untrusted accounts from launching Pardus Pen
- Review and constrain any wrapper scripts or launchers that pass unsanitized parameters to Pardus Pen
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.