Medium [CVE-2026-55798] Arbitrary command injection via shell metacharacters in file paths
This medium-severity Red Hat Linux advisory covers CVE-2026-55798.
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
Pillow is a Python imaging library. Prior to 12.3.0, WindowsViewer.get_command() constructed a cmd.exe shell command by directly embedding a file path into an f-string without escaping and passed the result to subprocess.
Popen(..., shell=True), allowing shell metacharacters in the file path to inject arbitrary cmd.exe commands. This issue is fixed in version 12.3.0.
An attacker could exploit this to execute unauthorized commands on the system. The vulnerability is specific to the Windows platform; the Linux (UnixViewer) and macOS (MacViewer) equivalents already apply proper shell quoting.
Red Hat severity: Moderate — CVSS 4.5 (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L). Weakness: CWE-78.
Red Hat lists Exploit Intelligence; Lightspeed Core; OpenShift Lightspeed; Red Hat AI Inference Server; Red Hat Ansible Automation Platform 2; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux AI (RHEL AI) 3; Red Hat OpenShift AI (RHOAI); Red Hat Quay 3; Red Hat Satellite 6 as not affected.
- < 12.3.0
Official advisory · high-confidence parse· fetched 11 days ago·verify at source
Mitigation checklist
- This vulnerability is specific to the WindowsViewer class in Pillow, which is only invoked on Windows systems. Red Hat products ship and run on Linux, where the UnixViewer class is used instead, which properly applies shlex.quote() to file paths. The vulnerable Windows code path is not reachable on Red Hat's supported platforms. Users can upgrade to Pillow 12.3.0 or later, which adds proper escaping to the Windows code path.
Official advisory · high-confidence parse· fetched 11 days ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.