How severe is CVE-2026-55798?

CVE-2026-55798 has a CVSS 3.x base score of 4.5, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-55798 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-55798?

CVE-2026-55798 affects Python Pillow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-55798?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-55798 published?

CVE-2026-55798 was published on 2026-07-06 and last updated on 2026-07-07.

CVE-2026-55798

CVE-2026-55798 is a medium-severity vulnerability in Python Pillow with a CVSS 3.x base score of 4.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: Medium (CVSS 3.x base score 4.5)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Python Pillow
Published: 2026-07-06
Last modified: 2026-07-07

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.

Frequently asked questions

What is CVE-2026-55798?: 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.
How severe is CVE-2026-55798?: CVE-2026-55798 has a CVSS 3.x base score of 4.5, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-55798 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-55798?: CVE-2026-55798 affects Python Pillow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-55798?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-55798 published?: CVE-2026-55798 was published on 2026-07-06 and last updated on 2026-07-07.

References

Affected products (1)

cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*

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