Vvveb CMS: Unrestricted Upload of File with Dangerous Type
CVE-2026-6257 is a critical-severity unrestricted upload of file with dangerous type vulnerability in Vvveb CMS from Vvveb, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 1.0.8.2 as the first without the flaw, so updating Vvveb CMS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Vvveb CMS to 1.0.8.2 or a later version.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.2 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 9.1 | Critical | CNA (vulncheck.com) |
Official description
Vvveb CMS before 1.0.8.2 contains a remote code execution vulnerability in its media management functionality where a missing return statement in the file rename handler allows authenticated attackers to rename files to blocked extensions .php or .htaccess. Attackers can exploit this logic flaw by first uploading a text file and renaming it to .htaccess to inject Apache directives that register PHP-executable MIME types, then uploading another file and renaming it to .php to execute arbitrary operating system commands as the www-data user.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Unrestricted Upload of File with Dangerous Type
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
How developers prevent this class of flaw
- Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.
More Unrestricted Upload of File with Dangerous Type vulnerabilities (CWE-434)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in Vvveb CMS
- 8.8 High severity
Recent Unrestricted Upload of File with Dangerous Type vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 8.1 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.2 High severity
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