CVE-2026-40520 Vulnerability Analysis & Exploit Details

CVE-2026-40520
Vulnerability Scoring

7.2
/10
Very High Risk

Highly exploitable, CVE-2026-40520 poses a critical security risk that could lead to severe breaches.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: High
    High-level privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-40520 Details

Status: Analyzed

Last updated: 🕓 23 Apr 2026, 16:27 UTC
Originally published on: 🕐 21 Apr 2026, 13:16 UTC

Time between publication and last update: 2 days

CVSS Release: version 3

CVSS3 Source

disclosure@vulncheck.com

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CVE-2026-40520 Vulnerability Summary

CVE-2026-40520: FreePBX api module version 17.0.8 and prior contain a command injection vulnerability in the initiateGqlAPIProcess() function where GraphQL mutation input fields are passed directly to shell_exec() without sanitization or escaping. An authenticated user with a valid bearer token can send a GraphQL moduleOperations mutation with backtick-wrapped commands in the module field to execute arbitrary commands on the underlying host as the web server user.

Assessing the Risk of CVE-2026-40520

Access Complexity Graph

The exploitability of CVE-2026-40520 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-40520

The exploitability of CVE-2026-40520 is influenced by multiple factors. Security teams should analyze system configurations and apply appropriate countermeasures to mitigate threats.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-40520, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-40520, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-40520 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: High
    CVE-2026-40520 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: High
    CVE-2026-40520 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-40520 References

External References

CWE Common Weakness Enumeration

CWE-78

CAPEC Common Attack Pattern Enumeration and Classification

  • Command Line Execution through SQL Injection CAPEC-108 An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
  • Command Delimiters CAPEC-15 An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or denylist input validation, as opposed to allowlist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or denylist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
  • Exploiting Multiple Input Interpretation Layers CAPEC-43 An attacker supplies the target software with input data that contains sequences of special characters designed to bypass input validation logic. This exploit relies on the target making multiples passes over the input data and processing a "layer" of special characters with each pass. In this manner, the attacker can disguise input that would otherwise be rejected as invalid by concealing it with layers of special/escape characters that are stripped off by subsequent processing steps. The goal is to first discover cases where the input validation layer executes before one or more parsing layers. That is, user input may go through the following logic in an application: <parser1> --> <input validator> --> <parser2>. In such cases, the attacker will need to provide input that will pass through the input validator, but after passing through parser2, will be converted into something that the input validator was supposed to stop.
  • Argument Injection CAPEC-6 An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
  • OS Command Injection CAPEC-88 In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.

Vulnerable Configurations

  • cpe:2.3:a:freepbx:api:15.0.1:alpha1:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.1:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.1:alpha2:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.1:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.1:alpha3:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.1:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.1:alpha4:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.1:alpha4:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.2:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.2:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.2.1:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.2.1:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.1:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.1:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.2:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.2:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.3:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.3:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.4:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.4:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.5:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.5:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.6:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.6:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.7:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.7:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.8:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.8:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.9:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.9:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.10:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.10:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.11:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.11:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.12:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.12:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.13:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.13:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.14:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.14:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.15:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.15:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.16:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.16:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.17:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.17:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.18:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.18:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.19:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.19:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.20:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.20:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.21:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.21:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.3.22:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.3.22:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.4:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.4:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.5:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.5:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.6:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.6:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.7:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.7:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.8:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.8:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.9:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.9:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.10:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.10:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.11:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.11:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.12:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.12:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:15.0.13:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:15.0.13:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.2:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.2:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.3:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.3:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.1:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.1:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.2:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.2:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.3:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.3:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.4:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.4:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.5:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.5:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.6:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.6:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.7:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.7:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.8:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.8:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.9:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.9:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.4.10:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.4.10:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.5:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.5:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.6:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.6:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.7:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.7:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.8:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.8:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.9:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.9:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.10:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.10:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.11:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.11:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.12:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.12:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.13:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.13:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.14:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.14:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.15:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.15:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.16:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.16:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:16.0.17:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:16.0.17:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.1:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.1:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.2:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.2:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.3:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.3:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.4:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.4:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.5:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.5:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.6:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.6:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.1.7:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.1.7:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.2:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.2:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.3:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.3:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.4:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.4:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.5:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.5:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.6:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.6:*:*:*:*:*:*:*
  • cpe:2.3:a:freepbx:api:17.0.7:*:*:*:*:*:*:*
    cpe:2.3:a:freepbx:api:17.0.7:*:*:*:*:*:*:*

Protect Your Infrastructure against CVE-2026-40520: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2026-8288 – A vulnerability was determined in Open5GS up to 2.7.7. This affects the function gsm_handle_pdu_session_modification_qos_flow_descriptions of the f...
  • CVE-2025-9973 – Due to not validating the organization context when executing adaptive authentication flows, the WSO2 Identity Server allows adaptive authenticatio...
  • CVE-2025-10470 – The Magic Link authentication flow accepts multiple invalid authentication requests without adequate rate limiting or resource control, leading to ...
  • CVE-2026-6956 – ATutor is vulnerable to Reflected XSS in /install/install.php endpoint. An attacker can provide a specially crafted URL that, when opened, results ...
  • CVE-2026-6909 – ATutor is vulnerable to Reflected XSS in /install/upgrade.php endpoint. An attacker can provide a specially crafted URL that, when opened, results ...