CVE-2026-6257

Severity CVSS v4.0:

CRITICAL

Type:

CWE-434 Unrestricted Upload of File with Dangerous Type

Publication date:

20/04/2026

Last modified:

06/05/2026

Description

Vvveb CMS prior to v1.0.8.2 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.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:H/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 9.20 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:H/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): High
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): High
Availability (SA): None

Base Score 4.0

9.20

Severity 4.0

CRITICAL

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 9.10 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): High
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

9.10

Severity 3.x

CRITICAL

CVE-2026-6257

Description

Impact

References to Advisories, Solutions, and Tools