Quick answers
- Is CVE-2026-77929 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77929 being exploited in the wild.
- How severe is CVE-2026-77929?
- High severity, with a CVSS score of 8.8, published 18 September 2026.
- Which products and versions are affected?
- ClipBucket ClipBucket before 5.5.3-#182.
- Is there a fix for CVE-2026-77929?
- A patch was published on 2026-08-28: Fix released in version 5.5.3-#182 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-77929 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-77929?
- Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in the FileUpload::manageFile() function in fileupload.class.php, where MIME type validation is performed on uploaded files but the file extension is not properly updated after validation. An attacker can upload a PHP file with forged image magic bytes (MIME header) that passes MIME validation; the .php extension persists on disk and the file executes as PHP via PHP-FPM when accessed. This is a post-authentication remote code execution vulnerability requiring a valid user account. The vulnerability is fixed in version 5.5.3-#182 and later.
Affected products
- ClipBucket ClipBucket before 5.5.3-#182
Timeline
- 2026-09-18: disclosed
- 2026-08-28: patched: Fix released in version 5.5.3-#182