CVE-2026-12555 Overview
CVE-2026-12555 is a privilege escalation vulnerability affecting HP Easy Start for macOS versions prior to 2.16.7.260722. The flaw is categorized under [CWE-379] (Creation of Temporary File in Directory with Insecure Permissions). Successful exploitation allows a local attacker to elevate privileges on the affected macOS host. HP has released updated software to address the issue.
Critical Impact
Local attackers can leverage insecure temporary file handling in HP Easy Start for macOS to escalate privileges, compromising confidentiality, integrity, and availability of the host system.
Affected Products
- HP Easy Start for macOS versions prior to 2.16.7.260722
- macOS systems with vulnerable HP Easy Start installed
- Endpoints used to configure or provision HP printing devices
Discovery Timeline
- 2026-08-24 - CVE-2026-12555 published to NVD
- 2026-08-27 - Last updated in NVD database
Technical Details for CVE-2026-12555
Vulnerability Analysis
HP Easy Start for macOS creates or uses temporary files in a directory with insecure permissions. The weakness maps to [CWE-379], where files placed in a world-writable or predictable temporary location can be manipulated by unprivileged local users. When the vulnerable component runs with elevated rights, an attacker who controls the contents or path of these temporary files can influence privileged execution.
HP's advisory confirms the outcome is escalation of privilege. An attacker who gains code execution as a low-privileged user on macOS can leverage the flaw to reach higher-privileged contexts used by the HP Easy Start installer or helper components. HP addresses the issue in version 2.16.7.260722 and later.
Root Cause
The root cause is improper handling of temporary files inside a directory whose permissions do not restrict access to the owning user. Predictable paths and insufficient access controls allow a local, unprivileged process to plant, replace, or symlink content that a privileged HP Easy Start routine subsequently trusts. See the HP Security Bulletin for vendor-supplied technical context.
Attack Vector
Exploitation requires local access with low privileges on the macOS system running HP Easy Start. The attacker stages malicious content in the insecure temporary location and waits for or triggers the privileged component to consume it. No user interaction is required beyond normal application execution. The result is code execution or file operations in the security context of the privileged HP Easy Start process.
Detection Methods for CVE-2026-12555
Indicators of Compromise
- Unexpected files, symlinks, or hardlinks created by non-privileged users in temporary directories used by HP Easy Start
- HP Easy Start helper processes executing binaries or scripts from world-writable paths
- Installation or launch of HP Easy Start builds older than 2.16.7.260722
Detection Strategies
- Inventory macOS endpoints for HP Easy Start and flag any version prior to 2.16.7.260722
- Monitor for privileged process execution that reads or writes files under /tmp or /private/tmp owned by other users
- Alert on symlink creation targeting HP Easy Start temporary files or working directories
Monitoring Recommendations
- Enable file integrity monitoring for HP Easy Start install paths and temporary directories
- Correlate sudo, launchd, and helper tool activity with file writes originating from unprivileged users
- Review macOS unified logs for anomalous privilege transitions tied to HP Easy Start components
How to Mitigate CVE-2026-12555
Immediate Actions Required
- Upgrade HP Easy Start for macOS to version 2.16.7.260722 or later on all affected endpoints
- Remove HP Easy Start from macOS hosts where it is not required for active printer provisioning
- Audit user accounts on affected macOS systems and remove unnecessary local access
Patch Information
HP has released HP Easy Start for macOS version 2.16.7.260722 to remediate the issue. Refer to the HP Security Bulletin for download links and version guidance. Deploy the updated build through managed software distribution to ensure consistent coverage across the fleet.
Workarounds
- Restrict interactive local access on macOS systems that must run older HP Easy Start builds until patching is complete
- Uninstall HP Easy Start on shared or multi-user macOS endpoints where privileged provisioning is not needed
- Apply macOS endpoint hardening baselines that limit write access to shared temporary directories
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
