CVE-2026-54507 in Vvveb
Summary
by MITRE • 09/18/2026
Vvveb is a powerful and easy to use CMS with page builder to build websites, blogs or ecommerce stores. Prior to 1.0.8.5, the oEmbedProxy() handler in admin/controller/editor/editor.php accepts an attacker-controlled url parameter and passes it to getUrl(), while validateUrl() in system/functions.php checks only the hostname string and does not validate its resolved addresses. An authenticated admin-panel user with editor/* permission can invoke GET /admin/index.php?module=editor/editor&action=oEmbedProxy with a dotted hostname or normalized loopback form that resolves to a private, loopback, link-local, or reserved address, causing the server to issue an HTTP or HTTPS request and return the response body. Storefront users and anonymous visitors cannot invoke the endpoint, but no CSRF token is required because the action uses GET. This can disclose internal service responses or cloud instance metadata and associated credentials. This issue is fixed in version 1.0.8.5.
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Analysis
by VulDB Data Team • 09/18/2026
Vvveb CMS versions prior to 1.0.8.5 contain a critical Server-Side Request Forgery vulnerability within the oEmbedProxy handler located at admin/controller/editor/editor.php. The core technical flaw stems from insufficient validation of user-supplied URLs passed via the url parameter. While the system employs a validateUrl function in system/functions.php, this implementation performs only superficial checks on the hostname string itself without resolving the domain to its actual IP address or validating against private and reserved network ranges. This architectural oversight allows attackers to bypass standard security controls by utilizing specific DNS resolution techniques, such as using dotted decimal notation for IPv4 addresses or normalized loopback forms like 0x7f000001 instead of localhost. These formats resolve to internal addresses that the basic string check fails to flag as malicious because they do not match explicit blocklists based on standard domain names.
The operational impact of this vulnerability is severe, particularly given its accessibility within the administrative interface. Although exploitation requires an authenticated user with editor permissions or higher, many CMS deployments grant these privileges broadly to content managers who may have less security awareness than system administrators. Because the vulnerable endpoint utilizes a GET request and lacks Cross-Site Request Forgery protections such as anti-CSRF tokens, it is trivially exploitable through simple HTTP requests crafted by an attacker who has gained access to valid credentials or potentially through social engineering if session hijacking occurs. The vulnerability enables the server to act as a proxy for arbitrary outbound connections, effectively turning the web application into a pivot point for internal network reconnaissance and data exfiltration.
Attackers can leverage this flaw to probe internal services that are not exposed to the public internet but are accessible from the server's local network environment. This includes querying internal APIs, database management interfaces, or configuration endpoints running on localhost or other private IP ranges within the corporate LAN. Furthermore, in cloud computing environments where Vvveb might be deployed, this vulnerability allows attackers to access instance metadata services typically found at reserved addresses such as 169.254.169.254. Accessing these endpoints can lead to the disclosure of sensitive infrastructure details and associated credentials, including temporary security tokens, IAM role information, and other secrets that are automatically injected into running instances for management purposes. This compromises not only the specific web application but potentially the entire cloud instance it resides on.
To mitigate this risk, organizations must immediately upgrade Vvveb CMS to version 1.0.8.5 or later where the validation logic has been corrected to properly resolve hostnames and enforce strict allowlists for permitted IP address ranges. For deployments that cannot be upgraded instantly due to compatibility constraints, network-level controls should be implemented to restrict outbound HTTP and HTTPS traffic from the web server application user account. This can be achieved through firewall rules or container security policies that whitelist only known external domains required for legitimate oEmbed functionality while blocking access to private RFC 1918 address spaces, link-local addresses, and cloud metadata endpoints. Additionally, implementing strict Content Security Policy headers and ensuring that administrative interfaces require multi-factor authentication can reduce the attack surface by limiting the likelihood of credential compromise leading to exploitation.
This vulnerability aligns with CWE-918 Server-Side Request Forgery (SSRF), specifically reflecting weaknesses in input validation where only superficial checks are applied without considering network resolution outcomes. It also maps to MITRE ATT&CK technique T1504, which covers Web Service Discovery, as the attacker uses the proxy functionality to discover and interact with internal services that would otherwise remain hidden from external networks. The lack of CSRF protection further exacerbates the issue by facilitating automated exploitation once credentials are obtained, highlighting the importance of defense-in-depth strategies that combine robust input validation at the application layer with restrictive network policies at the infrastructure level.