Arbitrary file upload in Macwarrior Clipbucket-V5
CVE-2026-77929
ClipBucket v5 before 5.5.3-#182 contains a file upload vulnerability that allows authenticated users to achieve remote code execution by uploading a PHP file with valid image magic bytes through the photo upload endpoint. The FileUpload::manageFile() function in fileupload.class.php fails to update the file extension after MIME validation, allowing an attacker-controlled .php extension to persist on disk and execute as PHP via PHP-FPM when the uploaded file is retrieved.
Vulnerability class: Unrestricted File Upload
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.009 (61.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000
Affected products
Weakness classification (CWE)
References
- ClipBucket 5.5.3-#182 Release Notes (release-notes)
- Patch Commit (patch)
- www.vulncheck.com/advisories/clipbucket-remote-code-execution-via-photo-upload-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-77929?
- CVE-2026-77929 is a high-severity vulnerability in Macwarrior Clipbucket-V5, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.8/10. Published 2026-09-18.
- How severe is CVE-2026-77929?
- High severity. CVSS v3 base score is 8.8 out of 10.