CVE-2026-91103 in HPLIP
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 flaws, as they affect core functionalities used for managing printer drivers and related services on Linux-based systems, which are increasingly targeted in supply chain attacks and lateral movement scenarios within enterprise environments.
The technical flaw underlying many of these vulnerabilities stems from improper input validation and memory management practices inherent in how HPLIP processes data received from networked printers or local interfaces. When the software fails to adequately sanitize inputs before processing them into internal structures, it creates opportunities for buffer overflows or logic errors that can be leveraged by an attacker. This aligns with CWE-120 Buffer Copy without Checking Size of Input and CWE-94 Improper Control of Generation of Code, as malicious actors can craft specific print jobs or network packets containing shellcode or exploit payloads. By triggering these flaws, an adversary may execute arbitrary code within the context of the user running the HPLIP service, which often requires elevated privileges to interact with hardware devices and system resources effectively.
The operational impact of these vulnerabilities is profound, particularly in environments where printers are accessible over untrusted networks or where users have limited security awareness regarding print job submissions. Remote Code Execution allows an attacker to gain full control over the affected host, potentially installing backdoors, establishing persistence mechanisms, or using the compromised machine as a pivot point for further network intrusion. This capability is directly mapped to MITRE ATT&CK technique T1203 Exploitation for Client Execution and T1059 Command and Scripting Interpreter, enabling adversaries to automate attacks and maintain access without physical presence. The potential for privilege escalation means that even if initial exploitation occurs under a low-privilege user account, the attacker may leverage these flaws to gain root or system-level access, bypassing standard security controls such as User Account Control (UAC) equivalents on Linux systems like SELinux or AppArmor policies through improper confinement enforcement.
Furthermore, the risk of denial of service and information disclosure adds layers of operational disruption and intelligence gathering capabilities for attackers. Denial of Service conditions can be triggered by sending malformed data that causes the HPLIP processes to crash or hang, disrupting printing services and potentially affecting other dependent applications sharing system resources. This corresponds to MITRE ATT&CK technique T1499 Endpoint Denial of Service, which can be used as a distraction tactic during more complex attacks. Information disclosure vulnerabilities may allow attackers to read sensitive data stored in memory or on disk by the HPLIP process, including credentials, network configurations, and proprietary document contents, facilitating further reconnaissance activities mapped to MITRE ATT&CK technique T1005 Data from Local System.
Mitigation strategies must prioritize immediate patching of all affected HPLIP components through official vendor channels to ensure that the remediated code is deployed across all endpoints. Organizations should also implement network segmentation to restrict access to printing services, ensuring that only authorized devices and users can submit print jobs or interact with printer management interfaces. Additionally, enforcing strict application whitelisting and monitoring for unusual process behavior associated with HPLIP binaries can help detect exploitation attempts in real-time. Security teams should review system logs for signs of privilege escalation or unauthorized file modifications, particularly in directories where HPLIP stores configuration files and temporary data, to identify potential post-exploitation activities that may have occurred prior to patching.