CVE-2026-91099 in Linux Imaging and Printing Software
Summary
by MITRE • 09/16/2026
HP has identified and remediated multiple externally reported vulnerabilities within HPLIP. The findings affect several software components that could potentially enable remote code execution, privilege escalation, denial of service, information disclosure, or unauthorized file modification under certain conditions.
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Analysis
by VulDB Data Team • 09/16/2026
Hewlett-Packard has addressed a cluster of security flaws identified in the HP Linux Imaging and Printing (HPLIP) suite, resolving issues reported by external researchers that pose significant risks to system integrity and confidentiality. These vulnerabilities span multiple software components within the HPLIP ecosystem, creating attack surfaces that can be exploited under specific conditions to achieve severe outcomes including remote code execution, privilege escalation, denial of service, information disclosure, and unauthorized file modification. The remediation effort underscores the critical nature of these defects in a widely deployed printing subsystem that interacts deeply with operating system kernels and user-space applications.
The potential for remote code execution represents one of the most critical risks associated with these vulnerabilities. If an attacker can trigger specific input vectors within HPLIP components, they may execute arbitrary commands on the target machine with the privileges of the application process. This aligns closely with CWE-94 Improper Control of Generation of Code (Code Injection) and is often categorized under MITRE ATT&CK technique T1059 Command and Scripting Interpreter if shell access is gained or T1203 Exploitation for Client Execution if the attack targets a client-side component. The ability to execute code remotely transforms what might otherwise be a local configuration issue into a vector for full system compromise, allowing attackers to install malware, establish persistence mechanisms, or pivot further into internal networks.
Privilege escalation is another major concern highlighted by these findings. HPLIP often runs with elevated privileges to manage hardware interfaces and print queues effectively. Vulnerabilities that allow an unprivileged user to manipulate memory structures or exploit logic errors in privileged components can lead to a gain of administrative rights. This scenario corresponds directly to CWE-269 Improper Privilege Management and is frequently mapped to MITRE ATT&CK technique T1068 Exploitation for Privilege Escalation. By leveraging these flaws, an attacker could bypass security controls designed to restrict user actions, potentially gaining access to sensitive system files or modifying critical configurations that affect the entire host environment.
Denial of service capabilities inherent in some of these vulnerabilities allow attackers to disrupt the availability of printing services and associated network resources. Through techniques such as buffer overflows or resource exhaustion attacks, malicious actors can crash HPLIP processes or consume excessive CPU and memory resources on the target system. This falls under CWE-400 Uncontrolled Resource Consumption and maps to MITRE ATT&CK technique T1499 Endpoint Denial of Service. The impact extends beyond simple service interruption; it can degrade overall system performance, prevent legitimate users from accessing printers, and create opportunities for further exploitation while the system is in a degraded state or undergoing recovery procedures that may expose additional weaknesses.
Information disclosure vulnerabilities enable unauthorized access to sensitive data stored on or processed by systems running HPLIP. This could include credentials, network configuration details, or proprietary document content being printed through vulnerable components. Such flaws are typically classified under CWE-200 Exposure of Sensitive Information to an Unauthorized Actor and align with MITRE ATT&CK technique T1537 Transfer Data to Cloud Account if data is exfiltrated externally or T1005 Data from Local System. The leakage of this information can facilitate subsequent attacks, such as credential stuffing or targeted phishing campaigns, thereby amplifying the initial impact of the vulnerability beyond its immediate scope.
Unauthorized file modification presents a risk where attackers alter system files, configuration settings, or print job data without proper authorization. This capability undermines the integrity of the operating environment and is categorized under CWE-94 Improper Control of Generation of Code if it involves injecting malicious content into executable files, or more broadly under CWE-732 Incorrect Permission Assignment for Critical Resource. In terms of MITRE ATT&CK, this relates to techniques like T1074 Data Staged or T1565 Data Manipulation. The ability to modify files arbitrarily can lead to persistent backdoors, corrupted print outputs that carry malicious payloads when opened by users, or the disruption of critical system operations dependent on specific file states.
Mitigation strategies for these vulnerabilities prioritize timely patching and strict access controls. Organizations should immediately apply the latest HPLIP updates provided by HP to close the identified gaps in software components. Additionally, implementing principle of least privilege is crucial; running HPLIP services with minimal required permissions can limit the impact if a vulnerability is exploited. Network segmentation helps isolate printing infrastructure from general corporate networks, reducing the attack surface for remote exploitation. Regular security audits and monitoring for anomalous behavior related to print spooler activity or unexpected process executions provide early detection capabilities against attempts to leverage these flaws.