CVE-2026-89026
Received Received - Intake

Hard-Coded JWT Key in Issabel Framework

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: VulnCheck

Description
The Issabel Framework, the web framework supporting Issabel PBX software, before commit b97dbaf contains a hard-coded HS256 JWT signing key in the pbxapi index.php file that is identical across every installation, allowing unauthenticated remote attackers to forge valid bearer tokens. Attackers can use the forged token to call the manager originate endpoint with the System application parameter, causing Asterisk to execute arbitrary OS commands as the Asterisk user. Exploitation evidence was first observed by the Shadowserver Foundation on 2026-09-09.

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Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
CVE-2026-89026
EUVD
EUVD-2026-78838

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
issabel pbx *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-321 The product uses a hard-coded, unchangeable cryptographic key.

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Executive Summary

CVE-2026-89026 is a critical vulnerability in the Issabel Framework, which supports Issabel PBX software. It involves a hard-coded HS256 JWT signing key in the pbxapi index.php file that is identical across all installations. This allows unauthenticated remote attackers to forge valid bearer tokens and exploit the manager originate endpoint to execute arbitrary OS commands as the Asterisk user.

Detection Guidance

Check for the presence of the hard-coded JWT key in pbxapi/index.php by searching for the string 'da893kasdfam43k29akdkfaFFlsdfhj23rasdf' in the file. If found, the system is vulnerable. Additionally, monitor network traffic for unauthorized calls to the manager originate endpoint with the System application parameter.

Impact Analysis

This vulnerability allows attackers to gain full control over the affected Issabel PBX system. They can execute arbitrary commands on the server with the privileges of the Asterisk user, potentially leading to data breaches, system compromise, or further network infiltration.

Compliance Impact

This vulnerability can severely impact compliance with GDPR and HIPAA by enabling unauthorized access to sensitive data. GDPR requires protecting personal data, while HIPAA mandates securing protected health information. A successful exploit could lead to data breaches, resulting in legal penalties, reputational damage, and loss of trust.

Mitigation Strategies

Apply the patch from commit b97dbaf0b71c1c36f841e672b664afbeb02773bd to replace the hard-coded JWT key with a dynamically loaded key from /etc/issabel.conf. Ensure the configuration file contains a valid 'pbxapijwtsecret' entry with at least 32 random bytes.

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