CVE-2026-6892: Canon CUPS Printer Driver macOS Privilege Escalation

Technical summary

CVE-2026-6892 involves improper symbolic link handling in Canon CUPS printer driver installers. The vulnerability exists in the installer code path where symlink resolution is not properly validated before permission modification operations. An attacker with local login privileges can position a crafted symbolic link in a predictable location during installation, causing the installer to follow the link and modify permissions on unintended target directories. The issue is classified as CWE-59 (Improper Link Resolution Before File Access), a classic symlink attack pattern. The CVSS 3.1 score of 5.0 reflects local-only attack vector, low complexity, and high integrity impact without confidentiality or availability consequences.

Business impact

For organizations deploying Canon printer drivers across macOS endpoints, this vulnerability creates a privilege escalation path. An employee or contractor with valid system access could exploit installation events to gain unauthorized write access to sensitive system or application directories. While not directly enabling remote compromise, the ability to modify directory permissions could facilitate subsequent attacks or lateral movement. The impact is constrained to organizations actively installing or updating these specific printer drivers, but any exploitation would likely require remediation of unauthorized permission changes.

Affected systems

Canon PIXUS iX6800 Series CUPS Printer Driver for macOS Version 16.91.0.0 and earlier (Japan region); Canon PIXMA MG2500 Series and iX6800 Series CUPS Printer Driver for macOS Version 16.91.0.0 and earlier (US and Europe regions). The vulnerability affects the driver installer component, not the runtime driver itself, so only systems actively performing driver installation or updates are exposed during the window of exploitation.

Exploitability

Exploitability is moderate and situational. The attack requires: (1) local login access to the target macOS system, (2) knowledge of where the installer will create or resolve symlinks, and (3) successful placement of a malicious symlink before the installer follows it. User interaction is required—the installer must be launched. An attacker cannot exploit this remotely, and the attack window is limited to the installation process. No public exploit code is known, and this CVE is not listed on the KEV catalog, indicating no evidence of active exploitation in the wild as of the publication date.

Remediation

Update Canon CUPS printer drivers to versions newer than 16.91.0.0. Canon should have released patched versions for both the iX6800 Series (Japan) and the MG2500/iX6800 Series (US/Europe). Verify the specific patched version numbers through the Canon support portal for your region. During installation, ensure that no untrusted users have write access to the /tmp directory or other locations where the installer may resolve symlinks. Consider restricting printer driver installation to administrators or designated IT personnel.

Patch guidance

Check Canon's official support website for your region (Japan, US, or Europe) for driver version updates beyond 16.91.0.0 for your specific printer series. Download patches only from Canon's official download portal. Before deployment, test the patched installer in a controlled environment. For enterprise deployments, coordinate driver updates during a maintenance window and verify no symlinks exist in predictable installation paths (typically /tmp or the user's home directory .tmp areas). Document the pre- and post-update driver versions in your asset management system.

Detection guidance

Monitor for suspicious symbolic link creation in common temporary directories (/tmp, /var/tmp, ~/Library/Caches) during or immediately before Canon printer driver installation. Audit unexpected permission changes on system directories post-installation. Log installer execution and correlate with permission modification events. Organizations with EDR or file integrity monitoring should flag instances where the CUPS printer driver installer modifies permissions outside its expected scope. Review system.log and install.log for any warnings about symlink traversal or permission errors during driver setup.

Why prioritize this

Assign medium priority. While the CVSS score is 5.0 (medium) and exploitation requires local access, the ability to escalate permissions across directory boundaries could enable further compromise. Prioritize this for systems where non-administrative users have login access and where printer driver installation is frequent or automated. Organizations with strict local access controls or air-gapped systems can defer this below other critical patches, but government, finance, and healthcare sectors with shared workstations should treat this as higher priority.

Risk score, explained

The CVSS 3.1 score of 5.0 reflects a local-only attack vector (AV:L), low attack complexity (AC:L), and requirement for low privileges plus user interaction (PR:L, UI:R). The high integrity impact (I:H) drives the score above low; however, no confidentiality impact (C:N) and no availability impact (A:N) prevent it from reaching high or critical severity. The score appropriately captures that an authenticated local user with modest effort can corrupt file permissions, but this alone does not compromise system confidentiality or availability directly.

Frequently asked questions