CVE-2026-91098: HP Linux Imaging and Printing RCE Vulnerability

CVE-2026-91098 Overview

CVE-2026-91098 affects HP Linux Imaging and Printing (HPLIP), the open-source software suite that provides printing, scanning, and fax capabilities for HP devices on Linux systems. HP identified and remediated multiple externally reported vulnerabilities within HPLIP that impact several software components. The flaws could enable remote code execution, privilege escalation, denial of service, information disclosure, or unauthorized file modification under specific conditions. The root weakness is classified as a heap-based buffer overflow [CWE-122]. Successful exploitation requires user interaction and can be triggered over the network.

Critical Impact
Attackers can achieve remote code execution with high confidentiality, integrity, and availability impact on affected HPLIP installations when a user interacts with attacker-supplied input.

Affected Products

HP Linux Imaging and Printing (HPLIP) software suite
HP printer, scanner, and multifunction devices managed through HPLIP on Linux
Linux distributions bundling vulnerable HPLIP components

Discovery Timeline

2026-09-16 - CVE-2026-91098 published to NVD
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-91098

Vulnerability Analysis

CVE-2026-91098 is a heap-based buffer overflow [CWE-122] within HPLIP components. The weakness occurs when the software writes data beyond the boundaries of a heap-allocated buffer. This overwrites adjacent heap metadata or object state and can allow an attacker to control program flow. HP's advisory groups multiple externally reported vulnerabilities together, meaning several code paths share the same underlying memory safety issue. The consequences span remote code execution, privilege escalation, denial of service, information disclosure, and unauthorized file modification depending on which component processes the malicious input.

Root Cause

The root cause is improper validation of input size before copying data into a fixed-size heap buffer. HPLIP parses printer configuration data, device responses, and protocol messages from multiple sources. When a length field or delimiter is not checked against the destination buffer, the copy operation overruns the allocation. Heap metadata corruption then becomes exploitable through standard glibc allocator techniques.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker delivers a crafted payload that HPLIP processes when a user prints, scans, or communicates with a manipulated device. The interaction requirement means exploitation depends on a user initiating an operation that touches attacker-controlled data. No code example is published for this issue. Refer to the HP Security Bulletin for component-level technical details.

Detection Methods for CVE-2026-91098

Indicators of Compromise

Unexpected hplip or hp-* process crashes with SIGSEGV or SIGABRT in system logs
New or modified files under HPLIP working directories such as /var/lib/hp/ or user ~/.hplip/ created outside normal operations
Outbound connections from HPLIP daemons to non-printer hosts
Privilege escalation events where child processes of HPLIP run with unexpected UIDs

Detection Strategies

Monitor process telemetry for HPLIP binaries spawning shells or interpreters such as bash, sh, or python
Alert on core dump generation from HPLIP components as evidence of memory corruption attempts
Inspect CUPS and IPP traffic for oversized attribute values that could trigger buffer overflows

Monitoring Recommendations

Enable auditd rules on HPLIP binaries and configuration paths to capture execve and file modification events
Centralize syslog and journald output covering cupsd and hplip services for behavioral analysis
Track package inventory to verify HPLIP versions across Linux endpoints and flag hosts running unpatched releases

How to Mitigate CVE-2026-91098

Immediate Actions Required

Apply the HPLIP security update referenced in the HP Security Bulletin as soon as it is available for your distribution
Inventory Linux endpoints running HPLIP and prioritize patching hosts that accept print or scan input from untrusted networks
Restrict network access to HPLIP and CUPS services to trusted management segments

Patch Information

HP has remediated the vulnerabilities within HPLIP. Consult the HP Security Bulletin for fixed versions and distribution-specific package availability. Coordinate with your Linux vendor for backported updates through the standard package manager.

Workarounds

Disable HPLIP services on systems that do not require HP printing or scanning functionality using systemctl disable --now hplip.service
Block inbound connections to HPLIP listening ports at the host firewall until patches are applied
Limit user interaction with untrusted print jobs, scan sources, or device discovery responses

bash

# Configuration example: disable HPLIP services and verify version
sudo systemctl stop hplip.service
sudo systemctl disable hplip.service
hp-check -r | grep -i version