CVE-2025-70522

Executive Summary

CVE-2025-70522 is a Cross-Site Request Forgery (CSRF) vulnerability in the request handler of Fanvil x7a IP phone firmware version 2.6.0.1182. The device enforces no cross-origin resource protection on any state-changing request, so the browser same-origin boundary that would normally isolate one web application from another is effectively absent. Any actor who can convince an authenticated administrator to visit attacker-controlled content can silently drive the phone's management interface to perform privileged state changes — reconfiguring the device, altering its provisioning or account settings, or otherwise manipulating its configuration — with the administrator's own credentials and privileges. Because the flaw affects every state-changing endpoint and no public patch, PoC, or CVE metadata (CVSS, CWE, EPSS all unassigned at publication) is currently available, defenders must assume the device remains exposed until vendor remediation can be independently verified.

Technical Analysis

The vulnerable component is the HTTP request handler embedded in the Fanvil x7a firmware (version 2.6.0.1182). Per the NVD description, that handler "does not enforce any cross-origin resource protection for any state-changing request performed against the applications." In practical terms this indicates the web management application fails to implement the standard anti-CSRF control set: no unpredictable anti-CSRF token bound to the session, no strict validation of the Origin/Referer headers on mutating requests, and no SameSite-restricted session cookie behavior that would prevent the browser from attaching credentials to a cross-site request. The result is that the cross-origin boundary "can be completely bypassed" for any endpoint that changes state — configuration writes, account provisioning, and similar management operations.

Attack surface: the phone's local web management interface, normally reachable on the LAN (and, where the interface has been exposed, from untrusted networks). The vulnerability class is CSRF (CWE-352). The precursor condition is authentication: the attack relies on the browser of an already-authenticated administrator automatically attaching the session cookie to a forged request. Because the vendor/product strings in the source data are recorded as unknown and no CVE metadata (CVSS, CWE, EPSS) has been assigned, no code-level commit, function name, or parameter name is available for citation; the mechanism above is derived strictly from the stated class and the description's "no cross-origin protection on state-changing requests" claim.

Key characteristics that elevate this beyond a generic CSRF finding:

• Universality: the description states protection is absent for any state-changing request, not a single endpoint, so the entire mutation surface of the management application is in scope.
• No token barrier: without per-session tokens, an attacker does not need to read or predict any secret — only to know or guess the target endpoint's shape.
• Session inheritance: the forged request executes with the victim administrator's full privileges, so the blast radius equals the administrator's own configuration authority.

Exploitation Scenarios

No public PoC is available for CVE-2025-70522; the chain below is inferred from the CSRF vulnerability class and the NVD description.

1. Reconnaissance / target identification. The attacker identifies reachable Fanvil x7a phones, typically by scanning internal or misconfigured external networks for the device management interface and fingerprinting the Fanvil x7a web UI. The attacker also needs to know (or discover) the shape of the state-changing endpoint — the HTTP method and path used to submit configuration changes — which for a web management UI is generally observable by anyone who can reach the interface, or inferable from device documentation.

2. Triggering the flaw. The attacker hosts a malicious page, email, or link. When an administrator who is currently logged into the phone's web interface loads that content, the victim's browser issues a request to the phone's management endpoint. Because the handler enforces no cross-origin protection, the phone accepts the cross-origin request and processes it as a legitimate state change; the browser automatically includes the administrator's session cookie, so no credential theft, password cracking, or authentication bypass is required. The attacker never needs to read a response — this is a blind CSRF, and the absence of anti-CSRF tokens means no value must be known in advance.

3. Payload / execution at the class level. The payload is a forged, state-changing request delivered through the victim's browser rather than an exploit that executes code directly. There are no CVE-specific function, parameter, or path names disclosed in the source data, so no concrete endpoint is asserted here. In a phone management interface, the categories of state-changing requests an attacker would target are configuration writes and account/settings modifications that the administrator's session is authorized to perform.

4. Post-exploitation impact. Whatever configuration the administrator could legitimately change, the attacker can change on the victim's behalf: altering the phone's configuration, provisioning, account, or network-related settings. If the attacker can direct provisioning-related settings at infrastructure they control, they may be able to influence what the device subsequently downloads or trusts — a persistence vector that outlives the original forged request, though this depends on capabilities not detailed in the source data. Affected devices sit on the same network as the administrator's browser, so the practical blast radius is every device whose admin is social-engineered into the attack.

Impact Assessment

• Confidentiality/Integrity/Availability (CVSS): No official CVSS score or vector has been assigned as of publication. The illustrative vector provided in this report's metadata reflects a standard CSRF profile — network-reachable, low complexity, no privileges required, user interaction required — with high confidentiality, integrity, and availability impact because full administrative configuration control over a phone can expose call data, redirect communications, and render the device unusable. It must not be treated as an authoritative NVD score.
• Business impact: Compromise of IP telephony endpoints can disrupt voice communications, redirect or expose calls, and subvert an organization's telephony configuration. For regulated environments, unauthorized configuration changes to communications equipment may carry compliance and audit consequences.
• Blast radius: Every Fanvil x7a running firmware 2.6.0.1182 whose management interface is reachable and whose administrator can be lured into loading attacker content. Since the flaw is universal across state-changing endpoints, containment via "block one URL" is not viable.
• Exploitability context: No public PoC, no Nuclei template, no KEV listing, and no EPSS score are recorded, which suggests low current in-the-wild activity — but the attack requires only a crafted page and one authenticated click, so the barrier to weaponization is low regardless of current exploit availability.
• Exposure risk multiplier: If the management interface has been exposed beyond the trusted LAN, or if an admin's browser routinely visits external sites while logged in, the effective attack surface expands significantly.

Detection Guidance

Sigma Rule

title: Possible Cross-Site Request Forgery Against Fanvil x7a Management Interface
id: 9e2c1a74-7b3f-4c2a-9d51-8f0a2b6c4d10
status: experimental
description: Detects state-changing HTTP requests to the Fanvil x7a web management interface that arrive with a cross-origin Referer or no tokens, consistent with CVE-2025-70522 CSRF activity.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2025-70522
author: valtersit.com
date: 2025-01-01
tags:
  - attack.t1204.001
  - cve.2025-70522
logsource:
  category: webserver
  product: fanvil
detection:
  selection_method:
    cs-method:
      - POST
      - PUT
      - PATCH
      - DELETE
  selection_ua:
    cs-user-agent|contains:
      - 'Mozilla'
  selection_crossorigin:
    cs-referer|startswith:
      - 'http://'
      - 'https://'
  filter_own_origin:
    cs-referer|contains:
      - 'fanvil'
  condition: selection_method and selection_ua and selection_crossorigin and not filter_own_origin
fields:
  - c-ip
  - cs-referer
  - cs-uri-stem
  - cs-method
falsepositives:
  - Legitimate users accessing the management UI from a bookmark with a foreign Referer
  - Proxy or security-gateway rewriting of Referer headers
level: medium

YARA Rule

rule CVE_2025_70522_Fanvil_X7A_CSRF
{
    meta:
        description = "Identifies Fanvil x7a firmware v2.6.0.1182 artifacts and CSRF-trigger pages targeting state-changing management endpoints"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-70522"
        date = "2025-01-01"
        cve = "CVE-2025-70522"

    strings:
        $fw = "2.6.0.1182" ascii wide nocase
        $vendor = "Fanvil" ascii wide nocase
        $model = "x7a" ascii wide nocase
        $csrf1 = "auto-submit" ascii wide nocase
        $csrf2 = "new Image().src" ascii wide nocase
        $csrf3 = "document.forms[0].submit" ascii wide nocase

    condition:
        uint16(0) == 0x5A4D or $fw or ($vendor and $model) or (any of ($csrf*) and $model)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2025-70522 Fanvil x7a CSRF state-changing request with cross-origin Referer"; flow:established,to_server; http.method; content:"POST"; http.header; content:"Referer"; content:"Fanvil"; nocase; http.uri; pcre:"/(cgi-bin|goform|action|config|setup|admin)/Ui"; classtype:attempted-admin; reference:cve,2025-70522; reference:url,nvd.nist.gov/vuln/detail/CVE-2025-70522; sid:202570522; rev:1;)

alert http any any -> any any (msg:"CVE-2025-70522 Fanvil x7a CSRF suspected cross-origin state change POST without anti-CSRF token"; flow:established,to_server; http.method; content:"POST"; http.header; content:"Host"; content:"Fanvil"; nocase; pcre:"/^Referer\x3a\s+(?!https?:\/\/[^\/]*fanvil)/miH"; classtype:attempted-admin; reference:cve,2025-70522; sid:202570523; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=10m
  [ network where http.request.method in ("POST", "PUT", "PATCH", "DELETE")
      and http.request.headers.referer != null
      and not http.request.headers.referer : "*/fanvil*"
      and url.path : ("*cgi-bin*", "*goform*", "*config*", "*setup*", "*admin*", "*action*") ]
  [ network where http.request.method in ("GET", "POST")
      and http.response.status_code >= 200 ]

Splunk SPL Query

index=web OR index=proxy sourcetype=access_combined earliest=-24h
| eval method=upper(cs_method)
| where method IN ("POST","PUT","PATCH","DELETE")
| eval referer=coalesce(cs_Referer, referer)
| where isnotnull(referer) AND NOT match(referer, "(?i)/fanvil")
| where match(uri, "(?i)(cgi-bin|goform|config|setup|admin|action)")
| stats count min(_time) as first_seen max(_time) as last_seen values(uri) as uris values(referer) as referers by src_ip, method, dest_host
| where count >= 1
| sort - count

Wazuh OSSEC Rule

<group name="fanvil,cve-2025-70522,web,">
  <rule id="100522" level="10">
    <decoded_as>json</decoded_as>
    <field name="http.method">POST|PUT|PATCH|DELETE</field>
    <field name="http.referer" negate="yes">fanvil</field>
    <field name="http.useragent">Mozilla</field>
    <description>CVE-2025-70522: Possible CSRF state-changing request against Fanvil x7a management interface from a cross-origin referer.</description>
    <mitre>
      <id>T1204.001</id>
    </mitre>
    <group>cve_2025_70522,csrf,web_attack,</group>
  </rule>

  <rule id="100523" level="12">
    <decoded_as>json</decoded_as>
    <field name="http.method">POST</field>
    <field name="url.path">config|setup|admin|action|goform|cgi-bin</field>
    <field name="http.referer" negate="yes">fanvil</field>
    <description>CVE-2025-70522: High-confidence forged state-changing request targeting Fanvil x7a configuration endpoint.</description>
    <mitre>
      <id>T1204.001</id>
    </mitre>
    <group>cve_2025_70522,csrf,web_attack,</group>
  </rule>
</group>

Mitigation & Patch Guidance

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

1) Immediate mitigations (while no patch exists):

• Do not expose the Fanvil x7a management interface to untrusted networks; restrict it to a dedicated, isolated management VLAN or segment.
• Insert strict network controls (ACLs, firewall rules) so only authorized administrator hosts can reach the web management port.
• Treat the web UI as untrusted to browse: admins should not have other browser tabs/sites open while logged into the phone, and should log out immediately after configuration tasks.
• Where feasible, enforce authentication controls at a reverse proxy in front of the interface and require re-authentication for state-changing actions at that layer.
• Block or filter outbound browsing from administrative workstations used to manage these phones (egress allow-listing) to reduce the lure surface.

2) Patch/upgrade steps:

• Confirm the installed firmware version. Version 2.6.0.1182 is reported vulnerable. No fixed firmware version has been identified by any tracked source, so treat all current releases as potentially affected until the vendor publishes and you can independently verify a remediation.
• Monitor the Fanvil vendor advisory/support channels for a patched firmware release addressing CVE-2025-70522, then validate the fix (e.g., confirm anti-CSRF tokens and Origin/Referer enforcement on mutating requests) before fleet-wide rollout.
• Until a verified fix exists, do not assume upgrade alone resolves exposure; keep compensating controls in place.

3) Long-term hardening:

• Require that management interfaces enforce unpredictable per-session anti-CSRF tokens plus Origin/Referer validation and SameSite cookies on all mutating requests; include this in procurement requirements for IP telephony hardware.
• Adopt network segmentation and zero-trust access for all VoIP/telephony endpoints so management planes are never reachable from general user networks.
• Harden administrator browsers and workflow: dedicated management sessions, no shared admin accounts, MFA where the product supports it, and short idle timeouts.
• Maintain asset inventory of phone firmware versions and subscribe to vendor and CVE feeds to detect when an official patch becomes available.

References

• NVD — CVE-2025-70522: https://nvd.nist.gov/vuln/detail/CVE-2025-70522
• Fanvil official site / support (monitor for firmware advisories): https://www.fanvil.com/
• CWE-352 — Cross-Site Request Forgery (MITRE): https://cwe.mitre.org/data/definitions/352.html
• OWASP Cross-Site Request Forgery Prevention Cheat Sheet: https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Request_Forgery_Prevention_Cheat_Sheet.html
• CISA Known Exploited Vulnerabilities Catalog (check for future listing): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Note: No threat actor campaign or exploit-in-the-wild evidence is associated with CVE-2025-70522 in the available data; the CVE is not listed in CISA KEV, has no public PoC, no Nuclei template, and no exploit code as of publication.