VULNpocalypse

CVE-2025-49596: MCP Inspector proxy server lacks authentication between the Inspector client and proxy

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

The MCP inspector is a developer tool for testing and debugging MCP servers. Versions of MCP Inspector below 0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and proxy, allowing unauthenticated requests to launch MCP commands over stdio. Users should immediately upgrade to version 0.14.1 or later to address these vulnerabilities.

Description quoted from the CVE record (assigned by GitHub_M, published 2025-06-13).

Weakness: CWE-306: Missing Authentication for Critical Function

How it can be exploited

Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and a user must take an action. Impact: confidentiality high, integrity high, availability high. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: total.

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-09370, CNNVD-202506-1790, EUVD-2025-20870, GHSA-232v-j27c-5pp6, GHSA-7f8r-222p-6f5g

VEDAS cluster: VEDAS:BLAZINGBANTAM

Exploit Observer links 7 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (7)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (3)

Vulnerability databases and vendor advisories (9)

Catalogue entries, not exploit evidence.

107 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.445
likely to be attacked soon
VEDAS
0.981
strong exploit evidence
On CISA KEV
Not listed
Detection rule
Nuclei · Suricata

Who is affected

ProductAffectedNot affected
modelcontextprotocol inspectorversion < 0.14.1Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: сообщество_свободного_программного_обеспечения mcp_inspector.

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

MCP inspector - Missing Authentication

The MCP inspector is a developer tool for testing and debugging MCP servers. Versions of MCP Inspector below 0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and proxy, allowing unauthenticated requests to launch MCP commands over stdio.

Name and description quoted from the template, written by VEDAS.

The template sends 3 requests (GET /, GET {{js}}, GET /sse?transportType=stdio&command=echo&args[]=hello-from-brower); it decides using dsl, regex matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2025-49596.yaml
Show the template (85 lines)
yaml
id: CVE-2025-49596

info:
  name: "MCP inspector - Missing Authentication"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    The MCP inspector is a developer tool for testing and debugging MCP servers. Versions of MCP Inspector below
    0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and
    proxy, allowing unauthenticated requests to launch MCP commands over stdio.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2025-49596&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=mcp&match=exact
  classification:
    cve-id: CVE-2025-49596
    cwe-id: CWE-306
  metadata:
    verified: false
  tags: cve,cve2025,mcp,anthropic,unauth,passive,vkev,vuln,ai
flow: http(1) && http(2) && http(3)

http:
  - method: GET
    path:
      - "{{BaseURL}}"

    host-redirects: true
    max-redirects: 2
    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - contains(body,"MCP Inspector")
        condition: and
        internal: true

    extractors:
      - type: regex
        name: js
        group: 1
        part: body
        regex:
          - 'src="([^"]+\.js)"'
        internal: true

  - method: GET
    path:
      - "{{BaseURL}}{{js}}"

    matchers:
      - type: dsl
        dsl:
          - status_code == 200
          - compare_versions(version, '< 0.14.0')
        condition: and
        internal: true

    extractors:
      - type: regex
        name: version
        internal: true
        group: 1
        part: body
        regex:
          - 'const\s+version\s*=\s*"([0-9]+\.[0-9]+\.[0-9]+)'

  - method: GET
    path:
      - "{{BaseURL}}/sse?transportType=stdio&command=echo&args[]=hello-from-brower"

    matchers:
      - type: dsl
        dsl:
          - contains_all(body,"endpoint","/message?sessionId=")
          - status_code == 200
        condition: and

    extractors:
      - type: regex
        name: session_id
        part: body
        group: 1
        regex:

          - '\/message\?sessionId=([a-z0-9-]+)' # Returns: Session ID as proof of execution

CVE-2025-49596.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2025-49596 MCP inspector - Missing Authentication. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2025-49596 MCP inspector - Missing Authentication"; flow:established,to_client; file.data; content:"src="; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2025-49596; reference:url,https://www.exploit.observer/?keyword=CVE-2025-49596&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=mcp&match=exact; sid:1011511; rev:1;)

CVE-2025-49596.rules on GitHub

Advisories on this CVE

References

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.