CVE-2026-54507

Executive Summary

CVE-2026-54507 is a server-side request forgery (SSRF) vulnerability in the Vvveb CMS, affecting versions prior to 1.0.8.5. The oEmbedProxy() handler in admin/controller/editor/editor.php accepts an attacker-controlled url parameter, passes it to getUrl(), and the associated validateUrl() check in system/functions.php only inspects the hostname string without validating the resolved IP address, allowing requests to private, loopback, link-local, or reserved addresses. The vulnerability requires an authenticated admin-panel user holding editor/* permission, meaning the immediate impact is privilege abuse and internally-routed network access rather than unauthenticated compromise.

Technical Analysis

The vulnerability class is CWE-918 (Server-Side Request Forgery). In Vvveb's editor controller, the oEmbedProxy() handler is designed to fetch remote content for oEmbed-style embedding within the page builder. It accepts a url parameter controlled by the caller and forwards it to a getUrl() helper. Before making the request, the application calls validateUrl() in system/functions.php, presumably to prevent requests to internal infrastructure. However, per the NVD description, validateUrl() "checks only the hostname string and does not validate its resolved addresses."

This is a classic string-based allow/deny check that is defeated by DNS rebinding or by using alternate textual representations of a target IP:

• Dotted hostnames or other normalized loopback forms (for example, representations of 127.0.0.1) that resolve, at request time, to a non-public address.
• Because only the hostname string is inspected, an attacker can supply a hostname that resolves to a private, loopback, link-local, or reserved IP range. The server then performs an HTTP or HTTPS request to the resolved address and returns the response body to the caller.

The endpoint is reachable via GET /admin/index.php?module=editor/editor&action=oEmbedProxy and, critically, "no CSRF token is required because the action uses GET." The action is behind the admin panel and requires editor/* permission, but requires no CSRF token, so any mechanism that causes an authenticated editor's browser to issue the GET (for example, an image tag or link) can trigger the request from the victim's session.

The technical root cause is a missing post-resolution IP validation step: safe implementations should resolve the hostname first and reject any result falling in RFC1918 (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), loopback (127.0.0.0/8), link-local (169.254.0.0/16, and IPv6 fd00::/8, fe80::/10), or otherwise reserved ranges before connecting. Vvveb's check, as described, does not do this.

The CVSS vector provided in the intelligence data is N/A; the vector shown in METADATA is an inferred 3.1 vector based on the described conditions (network reachable, high privileges required, no user interaction, changed scope due to the server acting on behalf of the attacker against internal services, high confidentiality impact, no integrity or availability impact). Analysts should treat this as an estimate, not an authoritative score, because the vendor/NVD did not publish one in the provided data.

Exploitation Scenarios

No public PoC or exploit code is available; the chain below is inferred from the vulnerability class and the details supplied in the NVD description.

1. Reconnaissance / target identification. An attacker who has already obtained a Vvveb admin-panel account with editor/* permission — or who can abuse an authenticated editor's session — identifies the instance running Vvveb < 1.0.8.5. Because the endpoint requires authentication, the entry condition is an account or session with editor-level access, not anonymous access.

2. Triggering the flaw. The attacker crafts a request to the known endpoint: GET /admin/index.php?module=editor/editor&action=oEmbedProxy&url=<attacker-controlled-url> The url parameter is forwarded to getUrl(). The validateUrl() check inspects only the hostname string, so the attacker supplies a hostname or normalized loopback form that passes the string check but resolves to a private, loopback, link-local, or reserved address.

Because the action uses GET and no CSRF token is required, the attacker can also attempt to have an authenticated user's browser issue the request (for example, by embedding the URL) — turning the single-user SSRF into a session-abuse vector against the editor's browser.

3. Execution and response retrieval. The server resolves the supplied hostname and issues an HTTP or HTTPS request to the resolved address. The response body is returned to the attacker through the oEmbed proxy response. The attacker thus obtains the response of the target internal service.

4. Post-exploitation. By iterating the url parameter, the attacker can probe internal services by their responses and, where cloud metadata endpoints are reachable on link-local addresses, attempt to retrieve instance metadata and associated credentials. The description explicitly notes this can "disclose internal service responses or cloud instance metadata and associated credentials." The impact is information disclosure; there is no described arbitrary code execution or data modification.

Because the flaw is triggered on the server side, the attacker does not need direct network access to the internal segments, only the ability to get an authenticated editor session or account.

Impact Assessment

• Confidentiality: High. The proxy returns full response bodies from internal services, including potential cloud instance metadata and credentials.
• Integrity: None described. The vulnerability does not describe write or modification capability.
• Availability: None described. No denial-of-service is described.
• Scope: Changed. The vulnerable component causes requests to systems that are outside the set of resources the application itself would normally reach (internal endpoints), which is why the inferred vector marks S:C.
• Privileges required: High. The endpoint is behind the admin panel and requires editor/* permission; anonymous visitors and storefront users cannot invoke it as described.
• Blast radius. The impact is bounded to what the SSRF can reach from the vulnerable Vvveb server: internal HTTP/HTTPS services, loopback-only administrative interfaces, and cloud metadata endpoints that are reachable from the instance. Credentials obtained from metadata (where applicable) can escalate beyond the initial editor account.

Business impact centers on information disclosure of internal services and, in cloud deployments, potential credential exposure enabling lateral movement. Although exploitation is authenticated, the absence of a CSRF token means the exploit does not require the attacker to directly hold the session cookie — an authenticated editor can be induced to trigger the request.

Detection Guidance

Sigma Rule

title: Vvveb CMS SSRF via editor oEmbedProxy Action
id: 8f2c1a94-7d3e-4b6a-9f21-5c1e0a7b4d10
status: experimental
description: Detects GET requests to the Vvveb editor oEmbedProxy endpoint that may indicate SSRF against internal addresses (CVE-2026-54507).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-54507
author: valtersit.com
date: 2026/02/14
tags:
  - attack.t1190
  - cve.2026.54507
logsource:
  category: webserver
detection:
  selection_endpoint:
    cs-method: 'GET'
    cs-uri-query|contains|all:
      - 'module=editor/editor'
      - 'action=oEmbedProxy'
  selection_suspicious_url:
    cs-uri-query|contains:
      - 'url=http://127.'
      - 'url=http://localhost'
      - 'url=http://0177'
      - 'url=http://0x7f'
      - 'url=http://[::1]'
      - 'url=http://169.254'
      - 'url=http://10.'
      - 'url=http://192.168.'
      - 'url=http://172.16.'
      - 'url=http://172.17.'
      - 'url=http://172.18.'
      - 'url=http://172.19.'
      - 'url=http://172.2'
      - 'url=http://172.30.'
      - 'url=http://172.31.'
  condition: selection_endpoint and selection_suspicious_url
falsepositives:
  - Legitimate editors embedding content from private oEmbed providers
level: high

YARA Rule

rule CVE_2026_54507_Vvveb_oEmbedProxy_SSRF
{
    meta:
        description = "Detects Vvveb editor oEmbedProxy SSRF exploitation attempts in HTTP request logs (CVE-2026-54507)"
        author = "valtersit.com"
        date = "2026-02-14"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-54507"
        severity = "high"

    strings:
        $ep1 = "module=editor/editor" ascii nocase
        $ep2 = "action=oEmbedProxy" ascii nocase
        $u1 = "url=http://127." ascii nocase
        $u2 = "url=http://localhost" ascii nocase
        $u3 = "url=http://169.254" ascii nocase
        $u4 = "url=http://10." ascii nocase
        $u5 = "url=http://192.168." ascii nocase
        $u6 = "url=http://[::1]" ascii nocase
        $u7 = "url=http://0x7f" ascii nocase
        $u8 = "url=http://0177" ascii nocase

    condition:
        $ep1 and $ep2 and any of ($u*)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-54507 Vvveb CMS oEmbedProxy SSRF Attempt"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"module=editor/editor"; http.uri; content:"action=oEmbedProxy"; http.uri; pcre:"/url=(http(s)?:\/\/)?(127\.|localhost|0177|0x7f|\[::1\]|169\.254\.|10\.|192\.168\.|172\.(1[6-9]|2[0-9]|3[01])\.)/Ui"; reference:cve,2026-54507; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-54507; classtype:attempted-recon; sid:202654507; rev:1;)

Elastic Detection

sequence by process.entity_id with maxspan=30s
  [ network where network.protocol == "http" and
      url.query : ("module=editor/editor" and "action=oEmbedProxy") and
      url.query : ("url=http://127.*", "url=http://localhost*", "url=http://169.254.*",
                   "url=http://10.*", "url=http://192.168.*", "url=http://[::1]*") ]

Splunk SPL Query

index=web OR index=proxy
| eval uri=coalesce(uri, url, request_url, cs_uri)
| where match(lower(uri), "module=editor/editor") AND match(lower(uri), "action=oembedproxy")
| rex field=uri "(?i)url=(?<ssrf_url>[^&\s]+)"
| where match(lower(ssrf_url), "^(https?://)?(127\.|localhost|0177|0x7f|\[::1\]|169\.254\.|10\.|192\.168\.|172\.(1[6-9]|2[0-9]|3[01])\.)")
| stats count min(_time) as first_seen max(_time) as last_seen values(ssrf_url) as targets by src_ip, uri
| convert ctime(first_seen) ctime(last_seen)
| sort - count

Wazuh OSSEC Rule

<group name="web,appsec,cve-2026-54507,">
  <rule id="202654507" level="12">
    <decoded_as>json</decoded_as>
    <field name="url">module=editor/editor</field>
    <field name="url">action=oEmbedProxy</field>
    <regex type="pcre2">url=(http(s)?:\/\/)?(127\.|localhost|0177|0x7f|\[::1\]|169\.254\.|10\.|192\.168\.|172\.(1[6-9]|2[0-9]|3[01])\.)</regex>
    <description>CVE-2026-54507: Vvveb CMS SSRF via editor oEmbedProxy action targeting an internal address</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>ssrf,attack,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate mitigations

   • Restrict or remove the editor/* permission from accounts that do not strictly require it, and audit existing admin-panel accounts for unnecessary editor access. Exploitation requires this permission.
   • Because the action uses GET and requires no CSRF token, add a CSRF requirement (or convert the action to POST) at the reverse proxy or application layer where possible, to prevent an authenticated editor's browser from being induced to issue the request.
   • At the network layer, block outbound HTTP/HTTPS from the Vvveb server to loopback, link-local, and private RFC1918 ranges using egress firewall rules or a proxy that enforces destination allowlists.
   • Enable instance metadata protection (e.g., IMDSv2 with a hop limit of 1 on cloud infrastructure) to reduce metadata-disclosure impact.

2. Patch / upgrade steps

   • The NVD description states the issue is fixed in version 1.0.8.5. Upgrade Vvveb to 1.0.8.5 or later. No vendor advisory, commit hash, or patch source is available from tracked data, so validate the fixed version against the official Vvveb repository/release channel before deployment.
   • There is currently no verified patch evidence in the tracked sources (0/4). Treat the "fixed in 1.0.8.5" statement as unverified until confirmed against the vendor.

3. Long-term hardening

   • Replace string-only URL validation with post-resolution IP validation: resolve the hostname and reject any address in loopback, link-local, private, or reserved ranges before connecting.
   • Apply response-size and timeout limits to the oEmbed proxy and log all proxied destination URLs for correlating SSRF attempts.
   • Enforce least-privilege for all editor/* and administrative roles, and add CSRF tokens to all state-changing and outbound-fetch actions.

References

• NVD — https://nvd.nist.gov/vuln/detail/CVE-2026-54507
• Vvveb CMS project (vendor product page / release channel) — confirm the 1.0.8.5 fix at the official Vvveb repository.
• CWE-918: Server-Side Request Forgery — https://cwe.mitre.org/data/definitions/918.html
• MITRE ATT&CK T1190: Exploit Public-Facing Application — https://attack.mitre.org/techniques/T1190/
• OWASP SSRF Prevention Cheat Sheet — https://cheatsheetseries.owasp.org/cheatsheets/Server_Side_Request_Forgery_Prevention_Cheat_Sheet.html

Threat actor campaigns / exploit-in-the-wild: none identified. CISA KEV status: NO. No public PoC, Nuclei template, or exploit code is available for this CVE in the supplied intelligence data.