Vulnerability · Published Jul 6, 2026 · Assigned by GitHub_M
CVE-2026-55798Pillow: WindowsViewer.get_command() OS command injection via unescaped shell path
Medium 4.5
In plain English
A medium-severity OS command injection in Pillow from python-pillow. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | pillow | 12.3.0 | GHSA-4x4j-2g7c-83w6 |
| PyPI | pillow | 12.3.0 | PYSEC-2026-2257 |
| Ubuntu:22.04:LTS | pillow | no fix listed | UBUNTU-CVE-2026-55798 |
| Ubuntu:24.04:LTS | pillow | no fix listed | UBUNTU-CVE-2026-55798 |
| Ubuntu:25.10 | pillow | no fix listed | UBUNTU-CVE-2026-55798 |
| Ubuntu:26.04:LTS | pillow | no fix listed | UBUNTU-CVE-2026-55798 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| python-pillow | Pillow | < 12.3.0 |
Weakness: CWE-78 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
References
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-4x4j-2g7c-83w6 x_refsource_CONFIRM
- https://github.com/python-pillow/Pillow/commit/8404ea5fe5df40fc34aa1e51403dd6fce0778b8a x_refsource_MISC
- https://github.com/python-pillow/Pillow/commit/88194166691b7b603529b8b036ab3ab9cedd2de4 x_refsource_MISC
- https://github.com/python-pillow/Pillow/commit/b0e06caa64c1405aa3da0bb1d2bd9a77ca22de7f x_refsource_MISC
- https://github.com/python-pillow/Pillow/blob/main/docs/releasenotes/12.3.0.rst x_refsource_MISC