Vulnerability report

Exploitation Attempts Observed Confirmed Confidence Not in CISA KEV

CVE-2026-89026

Issabel Framework Hard coded JWT Key RCE Remote Code Execution

Issabel Framework · affected before b97dbaf0b71c1c36f841e672b664afbeb02773bd

Watch CVE-2026-89026 Browse KEV feed
Severity
CVSS 9.3 · Critical
Confidence
Confirmed
Exploit status
Exploitation Attempts Observed in the Wild
EPSS
2.7%
First observed
22 Aug 2026
Last observed
03 Nov 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-89026 is an unauthenticated vulnerability affecting Issabel Framework.

Have exploitation attempts been observed?

Yes. Previdian sensors have observed 143 exploitation attempts, 15 unique attacker IPs, and 10 countries targeting CVE-2026-89026. First observed Aug 22, 2026; last observed Nov 03, 2026. Also reported by third-party sources. Confidence is confirmed.

Who is affected?

Issabel Framework affected before b97dbaf0b71c1c36f841e672b664afbeb02773bd.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

Issabel Framework Hard coded JWT Key RCE Remote Code Execution

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.

Issabel Foundation Affected
Issabel Framework
Before b97dbaf0b71c1c36f841e672b664afbeb02773bd
View vendor advisory (opens in new tab)
Published
15 Sep 2026
Attempts Observed Since
22 Aug 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

php nuclei_scanner

CVE References

  • CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-89026
  • Patch Commit github.com · Patch https://github.com/IssabelFoundation/framework/commit/b97dbaf0b71c1c3...
  • Third-Party Advisory — vulncheck.com vulncheck.com · Third-Party Advisory https://www.vulncheck.com/advisories/issabel-pbx-hard-coded-jwt-key-r...

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

Previdian sensor

Recorded 15 Sep 2026

Previdian sensors observed exploitation attempts targeting this vulnerability before a third-party report.

Exploitation Attempts Observed

Previdian sensor

First observed 22 Aug 2026

Previdian sensors observed exploitation attempts targeting this vulnerability.

Proof of concept available

GitHub

Recorded 16 Sep 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CVE First 2026-09-15 16:50 UTC
The Hacker News 2026-09-16 15:50 UTC
The Shadowserver 2026-09-21 00:00 UTC
Previdian Sensors 2026-09-23 11:38 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

Previdian Sensor Observations

Previdian sensor observations are exploitation attempts targeting this vulnerability. They do not show that the target was vulnerable or that the attempt succeeded. The cards and chart show volume, unique attackers, and daily activity.

143

Attempts observed

15

Unique attacker IPs

10

Attacker countries

AE · BR · CA · DE · FR · GE · ID · NL · SC · TR

3

Sensors observed

CVE-2026-89026 exploitation attempts over the last 77 days

Daily events observed by Previdian sensors

Updated 05 Nov 2026

0
4
0
0
0
0
0
0
0
4
4
4
2
0
0
4
0
0
0
0
0
0
0
0
0
0
8
0
0
0
0
0
4
2
4
2
0
0
0
0
0
30
0
0
0
0
0
0
0
0
0
0
0
0
0
13
0
0
0
0
0
0
0
0
0
0
0
2
4
12
16
8
4
8
4
0
0
21 Aug 6 Sep 22 Sep 8 Oct 5 Nov

First observed 22 Aug 2026 · Last observed 03 Nov 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
22
3
5

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-89026.yaml 24 Oct 2026

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

9.3 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS

2.7%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Use of Hard-coded Cryptographic Key CWE-321

Recent mention · The Hacker News

Attackers Exploit Issabel Framework Flaw Enabling Unauthenticated OS Command Execution

A critical security flaw in Issabel Framework, a web-based framework for the open-source unified communications PBX software, has come under active exploitation. The vulnerability in question is CVE-2026-89026 (CVSS v3.1 score: 9.8/CVSS v4.0 score: 9.3), which can allow an...

Read full advisory

All CVSS Scores

CVSS v4.0 9.3 Critical

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v3.1 9.8 Critical

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

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

AranFarzami/CVE-2026-89026

github · Created 2026-09-21 10:59:47 UTC · 1 stars · AI assessment 90%

PoC exploit and scanner for CVE-2026-89026, targeting the Issabel PBXAPI authentication vulnerability

cflowsec/CVE-2026-89026

github · Created 2026-09-16 17:34:33 UTC · 0 stars · AI assessment 90%

Issabel pbxapi hard coded JWT RCE POC

Issabel Framework - Hard-Coded PBX API JWT Key

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation attempts

  1. 04:31 UTC

    Nuclei template available

    Scanner coverage available

  2. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attempts reported by an external source

  3. 17:34 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 15:50 UTC

    KEV confirmed by The Hacker News

    Exploitation attempts reported by an external source

  5. 16:50 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party report of exploitation attempts

  6. 16:41 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 16:23 UTC

    CVE ID reserved

    Identifier reserved by the CNA

  8. 02:48 UTC

    Indicators of compromise added (15)

    Indicators of compromise recorded

  9. 02:48 UTC

    Observed by Previdian sensors

    Previdian sensors observed exploitation attempts targeting this vulnerability.

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-89026

Sample API response 
{
  "cve_id": "CVE-2026-89026",
  "confidence": "Confirmed",
  "cvss_score": 9.3,
  "cvss_estimated": false,
  "epss_score": 0.02699,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 143, "sensors": 3 }
}