Vulnerability in Issabel Foundation Framework

CVE-2026-89026

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.027 (85.9th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 85.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-89026: rose from 0.007 to 0.027.

EPSS over last 30 days · oldest: 0.007 · newest: 0.027 · change: +0.020

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-89026?
CVE-2026-89026 is a critical-severity vulnerability in Issabel Foundation Framework, classified under Use of Hard-coded Cryptographic Key. CVSS score: 9.8/10. Published 2026-09-15.
How severe is CVE-2026-89026?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-89026 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.