high CVSS 7.5

CVE-2025-21623·PHP vulnerability

ClipBucket V5 provides open source video hosting with PHP. Prior to 5.5.1 - 238, ClipBucket V5 allows unauthenticated attackers to change the template directory via a directory traversal, which results in a denial of service.

Severity
high
Software
PHP
Fixed in
5.5.1-238
Published
2025-01-07

Affected versions

From: 5.3

Until: 5.5.1-238

Fixed in: 5.5.1-238

How to fix this CVE

ClipBucket V5 versions prior to 5.5.1-238 are vulnerable to unauthenticated directory traversal attacks that allow attackers to redirect the template directory, causing denial of service. Upgrade PHP and ClipBucket to version 5.5.1-238 or later to patch this vulnerability. If you are running ClipBucket V5 in your PHP environment, ensure your deployment is updated immediately.

sudo dnf update php php-common php-cli php-fpm -y

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

POST|GET.*template.*\.\.\/|directory.*traversal.*template|template_dir=.*\/\.\.\/$

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Block HTTP requests containing directory traversal patterns in the 'template' or 'template_dir' parameters. Use ModSecurity rule: SecRule ARGS:template|ARGS:template_dir "@rx (?:\.\./|\.\.\\|%2e%2e[/\\])" "id:1001,phase:2,deny,status:403,msg:'ClipBucket Template Directory Traversal Attempt'"

How to check if you are affected

  1. Run 'php -v' to check the installed PHP version and verify ClipBucket version via admin panel or database query: SELECT value FROM clipbucket_settings WHERE name='version'
  2. Check if ClipBucket V5 is installed by looking for the clipbucket directory in your web root (typically /var/www/html or /home/*/public_html)
  3. Search web server logs for suspicious template directory parameter changes: grep -r 'template' /var/log/apache2/access.log | grep -i traversal
  4. Verify the patch was applied by confirming ClipBucket version is 5.5.1-238 or later in the admin settings or by checking: php -r 'include "includes/config.php"; echo CLIPBUCKET_VERSION;'

Indicators of compromise

  • POST parameter: template_dir with ../ sequence
  • GET parameter: template containing path traversal sequences
  • HTTP requests with Content-Type: application/x-www-form-urlencoded targeting template configuration endpoints

FAQ

What is CVE-2025-21623?

CVE-2025-21623 is a path traversal vulnerability in ClipBucket V5 that allows unauthenticated attackers to manipulate the template directory configuration, resulting in denial of service by breaking the application's rendering capabilities.

Is CVE-2025-21623 being actively exploited?

No, according to CISA's Known Exploited Vulnerabilities catalog, CVE-2025-21623 is not currently being actively exploited in the wild, and no public exploits are publicly available.

What versions of PHP are affected by CVE-2025-21623?

ClipBucket V5 versions 5.3 through 5.5.1-238 are affected. The vulnerability is fixed in version 5.5.1-238 and later.

How do I check if my server is vulnerable to CVE-2025-21623?

Run 'php -r "include 'includes/config.php'; echo CLIPBUCKET_VERSION;"' to display your ClipBucket version. If the version is between 5.3 and 5.5.1-237, your installation is vulnerable.

Does Defensia detect CVE-2025-21623?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If PHP and ClipBucket V5 are detected on a monitored server, CVE-2025-21623 will appear in your dashboard with remediation steps.

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References

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