CVE-2026-25728: ClipBucket v5 Affected by Remote Code Execution via Avatar/Background File Upload Race Condition

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-10 · updated 2026-06-17
Weakness: CWE-367

Description

ClipBucket v5 is an open source video sharing platform. Prior to 5.5.3 - #40, a Time-of-Check to Time-of-Use (TOCTOU) race condition vulnerability exists in ClipBucket's avatar and background image upload functionality. The application moves uploaded files to a web-accessible location before validating them, creating a window where an attacker can execute arbitrary PHP code before the file is deleted. The uploaded file was moved to a web-accessible path via move_uploaded_file(), then validated via ValidateImage(). If validation failed, the file was deleted via @unlink(). This vulnerability is fixed in 5.5.3 - #40.

Affected products

MacWarrior clipbucket-v5: from 5.3 before 5.5.3-40 — fixed in 5.5.3-40

How to fix

Upgrade to a fixed version: MacWarrior clipbucket-v5 5.5.3-40. Check the vendor advisory for mitigations.

References

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