CVE-2026-122137 in Powerlevel10k
Summary
by MITRE • 11/04/2026
Powerlevel10k before 1.20.19 contains an insecure temporary directory vulnerability in the bundled gitstatus/install script that reuses attacker-creatable directories when mktemp fails. Local attackers can pre-create the predictable gitstatus-install.tmp directory to replace the extracted gitstatusd binary, which then executes with the victim's privileges.
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Analysis
by VulDB Data Team • 11/04/2026
The Powerlevel10k shell theme distribution prior to version 1.20.19 contains a critical insecure temporary file creation vulnerability within its bundled installation script for the gitstatus component. This flaw stems from an improper handling of system calls used to generate unique filenames, specifically failing to enforce secure permissions or verify directory ownership when falling back to alternative paths after initial attempts fail. The underlying technical mechanism involves the use of mktemp without adequate safeguards against race conditions and predictable naming conventions. When the primary method for creating a temporary file fails due to environmental constraints such as full disk space or permission restrictions, the script defaults to using a static, hardcoded filename rather than generating a cryptographically secure random name within a properly secured directory. This behavior creates a classic insecure temporary file condition where an attacker can predict and pre-create the target path before the legitimate process attempts to write to it.
This vulnerability is classified under CWE-377, which describes Insecure Temporary File Creation, as well as CWE-59, Improper Link Resolution Before File Access or Symlink Follow, depending on whether symbolic links are exploited in conjunction with the predictable filename. The attack vector allows a local user who has access to the same filesystem namespace to execute a pre-conditioning step by creating the specific gitstatus-install.tmp file at the expected location. Because the installation script does not verify that it owns the directory or check for existing files before proceeding, it proceeds to overwrite this attacker-controlled placeholder with malicious content disguised as the legitimate gitstatusd binary. This represents a significant deviation from secure coding practices recommended in industry standards such as OWASP and NIST guidelines for system administration scripts, which mandate the use of mktemp with restrictive umask settings or explicit directory creation using mkdir -p with restricted permissions to prevent unauthorized access during file generation.
The operational impact of this vulnerability is severe, leading directly to Local Privilege Escalation if executed by a user with elevated privileges or resulting in arbitrary code execution within the context of the victim's shell environment. Since Powerlevel10k is often sourced in interactive shells and may be installed via scripts run with sudo or other elevation mechanisms, an attacker can manipulate the installation process to replace the gitstatusd binary—a background helper program responsible for providing fast Git status information—with a malicious executable. Once replaced, every subsequent invocation of the shell prompt that triggers the gitstatus check will execute the attacker's code under the privileges of the user running the terminal session. This effectively bypasses standard security controls by leveraging trusted software installation routines to inject malware into a high-privilege context without requiring direct exploitation of kernel vulnerabilities or network-based attacks.
Mitigation strategies require immediate updates to Powerlevel10k version 1.20.19 or later, where the developers have addressed this flaw by ensuring that temporary files are created in directories with restricted permissions and using unique, unpredictable filenames generated securely by the operating system. Administrators should also audit their shell configuration scripts for similar patterns of insecure temp file usage, particularly those relying on hardcoded paths like /tmp/gitstatus-install.tmp without verification steps. Implementing strict umask settings during script execution can further mitigate risks by ensuring that newly created files are not world-readable or writable. Additionally, organizations should enforce the principle of least privilege when running shell initialization scripts and consider using application whitelisting to prevent unauthorized binaries from executing in sensitive directories, thereby reducing the blast radius even if such a vulnerability is present in third-party tools like Powerlevel10k.