CVE-2026-100524

Executive Summary

CVE-2026-100524 is a cross-site request forgery (CSRF) vulnerability in the extensions manager component of the Cotonti content management system, affecting all versions through 1.0.0. The flaw allows an attacker to induce an authenticated administrator to perform state-changing actions—specifically installing, updating, pausing, or unpausing extensions—without any valid anti-CSRF token. With a CVSS base score of 5.4 (Medium) and no available patch, exploitation depends on social engineering an authenticated admin into visiting a malicious page, after which the attacker can manipulate the extension lifecycle on the target system.

Technical Analysis

Cotonti is a PHP/MySQL-based content management system. The vulnerability resides in the extensions manager, the administrative component responsible for managing CMS extension lifecycle operations. According to the NVD description, the extensions manager does not validate an anti-CSRF token when processing requests that install, update, pause, or unpause extensions.

Cross-site request forgery (CWE-352) occurs when a web application performs state-changing actions based solely on the browser's automatically attached session credentials, without requiring a separate, unpredictable, per-request token that an attacker cannot forge. In this case, the affected operations are administrative extension-management actions. Because the application does not require token validation for these requests, any authenticated administrator session becomes usable as an implicit authorization mechanism: a forged request sent from a third-party origin will be processed with the administrator's privileges.

The attack surface is the extension management functionality reachable by an authenticated administrator. The precise request method (GET or POST), parameter names, URL endpoints, and content of the extension-management requests are not disclosed in the available NVD description; therefore, only the vulnerability class and its general mechanism can be stated with confidence. The description explicitly notes that attackers can "craft links or embed images," which indicates the operations can be triggered via HTTP requests carrying session cookies—consistent with classic CSRF where the browser automatically supplies the target site's cookies regardless of the originating page.

Key characteristics derivable from the data:

• No anti-CSRF token validation on extension-management state changes.
• Operations affected: install, update, pause, and unpause of extensions.
• Trigger vector: attacker-controlled page (link or embedded image) visited by an authenticated administrator.
• Required precondition: an active, authenticated administrative session on the target Cotonti instance.
• Rated CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L — network-reachable, low complexity, no privileges required by the attacker, user interaction required, scope unchanged, no confidentiality impact, low integrity and low availability impact.

The integration and readiness of third-party extensions is a security-relevant administrative function. Because the CMS does not verify intent for these actions, the integrity of the extension ecosystem can be manipulated even though the attacker holds no credentials and no direct access to the target host.

Exploitation Scenarios

No public proof-of-concept or exploit code is available for this CVE. The attack chain below is inferred strictly from the vulnerability class (CSRF) and the NVD description, which states that attackers "can craft links or embed images to force administrators to install, update, pause, or unpause extensions by tricking them into visiting a malicious page while authenticated." No specific function names, parameters, endpoints, or file paths are invented here.

1. Reconnaissance / target identification The attacker identifies a Cotonti installation running a version through 1.0.0 and confirms that the extensions manager is reachable by an administrator. Public search engines and web-crawling services can be used to fingerprint Cotonti deployments (for example, by unique page content or site title). The attacker does not need any credentials.

2. Precondition / triggering the flaw class The flaw is triggered only while the victim administrator is authenticated to the target Cotonti instance. The attacker distributes a malicious page—via phishing email, a forum post, a social-engineering message, or a compromised website—containing either a hyperlink or an embedded image whose URL corresponds to the extension-management action. When the authenticated administrator visits that page (or loads that image), the browser automatically includes the administrator's Cotonti session cookies in the request. Because no anti-CSRF token is validated, the CMS processes the request as if the administrator had intentionally submitted it.

3. Execution method (vulnerability-class level) The forged request carries the extension-management action. Depending on the exact implementation—which the available description does not disclose—the action may be expressed as a GET link or as a POST-automated form submission. The four state-changing outcomes named in the description are:

• Install an extension (potentially introducing an attacker-chosen or attacker-referenced extension into the CMS).
• Update an extension (potentially replacing the current version with another).
• Pause an extension (disabling its functionality).
• Unpause an extension (re-enabling its functionality). No information about the request structure, parameter names, or the source of the installed/updated extension content is provided, so these specifics are not asserted.

4. Post-exploitation impact Successful exploitation yields low integrity and low availability impact (per CVSS: I:L/A:L). Consequences include unauthorized modification of the extension configuration, disabling of defensive or business-critical extensions (pause), re-enabling of previously deactivated functionality (unpause), or altering the installed extension set (install/update). If the install/update action permits sourcing an extension from an attacker-influenced location, this could escalate beyond the CVSS rating; however, no evidence in the provided data supports that escalation, and it is therefore not claimed. There is no confidentiality impact (C:N) and no scope change (S:U) according to the provided vector.

Impact Assessment

Business impact stems from unauthorized administrative actions against the CMS extension lifecycle. An attacker can, without credentials, alter which extensions are active or installed on a Cotonti instance, provided a privileged administrator can be induced to visit a malicious page while logged in. This undermines the trustworthiness of the CMS platform and any security controls delivered via extensions.

CVSS subscores (as provided):

• AV:N — exploitable over the network.
• AC:L — no special conditions beyond the described trigger.
• PR:N — the attacker needs no privileges on the target.
• UI:R — successful attack requires administrator interaction (visiting the malicious page).
• S:U — impact remains within the security scope of the vulnerable component.
• C:N — no confidentiality impact.
• I:L — limited integrity impact (extension state can be changed).
• A:L — limited availability impact (extensions can be paused/disabled).
• Base score 5.4 (Medium).

Affected systems: any Cotonti deployment running version 1.0.0 or earlier whose extensions manager is used by administrators and whose admin is susceptible to the described social-engineering vector. Blast radius is bounded by administrator session availability and by the set of state-changing actions exposed by the extensions manager. No CISA KEV listing, no public exploit code, and no known in-the-wild campaigns have been identified in the provided data.

Detection Guidance

Sigma Rule

title: Possible CSRF Abuse of Cotonti Extensions Manager
id: 9f1c2b7e-4a3d-4c8a-b6e1-cotonti-csrf-100524
status: experimental
description: Detects state-changing requests to the Cotonti extensions manager (install, update, pause, unpause) that lack a valid anti-CSRF token, consistent with CVE-2026-100524.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-100524
author: valtersit.com Threat Intelligence
date: 2026/01/01
logsource:
  category: webserver
detection:
  selection_path:
    cs-uri-stem|contains:
      - '/admin'
      - '/extensions'
  selection_action:
    cs-uri-query|contains:
      - 'install'
      - 'update'
      - 'pause'
      - 'unpause'
  filter_token:
    cs-uri-query|contains:
      - 'token='
      - 'csrf'
  condition: selection_path and selection_action and not filter_token
falsepositives:
  - Legitimate administrative workflows that use a different token parameter name
level: medium
tags:
  - attack.t1204.001
  - cwe.352

YARA Rule

rule CVE_2026_100524_Cotonti_CSRF
{
    meta:
        description = "Detects Cotonti extensions manager code lacking anti-CSRF token validation (CVE-2026-100524)"
        author = "valtersit.com Threat Intelligence"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-100524"
        date = "2026-01-01"
        severity = "medium"
    strings:
        $ext = "extensions" nocase
        $install = "install" nocase
        $update = "update" nocase
        $pause = "pause" nocase
        $unpause = "unpause" nocase
        $cot = "Cotonti" nocase
        $csrf = "csrf" nocase
        $token = "token" nocase
    condition:
        $cot and $ext and any of ($install, $update, $pause, $unpause)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-100524 Possible Cotonti Extensions Manager CSRF Attempt"; flow:to_server,established; http.uri; content:"/admin"; http.uri; content:"extension"; nocase; http.uri; pcre:"/(install|update|pause|unpause)/i"; threshold:type limit, track by_src, count 5, seconds 60; classtype:web-application-attack; reference:cve,2026-100524; sid:2026100524; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=30s
  [network where network.protocol == "http" and url.path : "*admin*" and url.path : "*extension*"]
  [network where network.protocol == "http" and url.query : ("*install*" or "*update*" or "*pause*" or "*unpause*")]

Splunk SPL Query

index=web sourcetype=access_combined
| eval uri=lower(uri)
| where (match(uri,"admin") AND match(uri,"extension"))
| where (match(uri,"install") OR match(uri,"update") OR match(uri,"pause") OR match(uri,"unpause"))
| where NOT match(uri,"token=")
| stats count earliest(_time) as first_seen latest(_time) as last_seen by clientip, uri
| where count > 1
| sort - count

Wazuh OSSEC Rule

<group name="web,cve-2026-100524,">
  <rule id="100524" level="10">
    <decoded_as>web-accesslog</decoded_as>
    <url>admin|extensions</url>
    <regex>install|update|pause|unpause</regex>
    <description>CVE-2026-100524: Possible CSRF request to Cotonti extensions manager from $(srcip)</description>
    <mitre>
      <id>T1204.001</id>
    </mitre>
    <group>cwe_352,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix, advisory, or workaround has been identified.

1. Immediate mitigations

• Require administrators to log out of the Cotonti admin panel when not actively in use, reducing the window in which a forged request can be delivered against an authenticated session.
• Educate administrators not to click untrusted links or load pages from untrusted origins while an authenticated Cotonti admin session is active.
• Restrict administrative access to trusted networks, VPN, or IP allowlists where feasible.
• Deploy network and host detection (Sigma/YARA/Suricata/Elastic/Splunk/Wazuh rules above) to identify anomalous extension-management requests that lack token parameters.
• Consider front-end controls that block or strip cross-origin requests to admin paths (for example, a reverse proxy enforcing same-site cookie attributes such as SameSite=Strict/Lax where the framework supports it).

2. Patch/upgrade steps

• No patch exists. Monitor the Cotonti project and its release channels for a fixed release covering CVE-2026-100524.
• When a patch is published, upgrade all Cotonti instances through 1.0.0 to the fixed version, and validate that the extensions manager enforces anti-CSRF token validation on install, update, pause, and unpause operations.
• If the maintainers publish an advisory or commit, apply it promptly and re-test the extension-management workflows.

3. Long-term hardening

• Implement application-wide anti-CSRF token validation for all state-changing administrative actions as a design requirement.
• Set session cookies with the SameSite attribute to limit cross-site request inclusion.
• Apply the principle of least privilege to administrative roles and separate extension-management capability from other admin functions.
• Add continuous vulnerability scanning and configuration monitoring for installed extensions.
• Adopt a software composition and CMS lifecycle policy to ensure timely upgrades and reduce reliance on end-of-life releases.

References

• NVD — CVE-2026-100524: https://nvd.nist.gov/vuln/detail/CVE-2026-100524
• MITRE CWE-352 (Cross-Site Request Forgery): 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
• MITRE ATT&CK — T1204.001 User Execution: Malicious Link: https://attack.mitre.org/techniques/T1204/001/
• Cotonti project site (monitor for security advisories and fixed releases): https://www.cotonti.com/

Threat actor campaigns / exploit-in-the-wild: None identified in the provided data. CISA KEV: NO. No public PoC, exploit code, or Nuclei template is available.