CVE-2026-44237Network attack vector

OAuth2 authentication bypass via unconditional client validation

Published May 29, 2026 · Updated May 29, 2026

Authentication bypass in the FreePBX api module before 17.0.8 allows remote authenticated users to obtain OAuth2 access tokens. The validateClient() method in ClientRepository.php returns true unconditionally, so token issuance accepts any client_secret for a known client_id. A valid randomized client_id and at least one configured OAuth2 application are required; the default gql scope permits full GraphQL read and write access.

CVSS severity8.1
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in the FreePBX api module before 17.0.8 allows remote authenticated users to obtain OAuth2 access tokens. The validateClient() method in ClientRepository.php returns true unconditionally, so token issuance accepts any client_secret for a known client_id. A valid randomized client_id and at least one configured OAuth2 application are required; the default gql scope permits full GraphQL read and write access.

The record

CVE
CVE-2026-44237
Published
May 29, 2026
Updated
May 29, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-1390, T1606
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
7.6GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1390Weak Authentication
T1606Forge Web Credentials

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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