Attackers Exploit Issabel Framework Flaw Enabling Unauthenticated OS Command Execution

Summary: A critical flaw in the Issabel Framework, CVE-2026-89026 with a CVSS v3.1 score of 9.8, lets unauthenticated remote attackers forge bearer tokens using a hard-coded HS256 JWT signing key found in the pbxapi index.php file and identical across every installation. VulnCheck said attackers can use the forged token to call the '/pbxapi/manager/originate' endpoint with the System application parameter, causing Asterisk to execute arbitrary OS commands as the Asterisk user; a patch pushed on August 1, 2026 replaces the hard-coded key with one stored in '/etc/issabel.conf', and the Shadowserver Foundation first observed exploitation on September 9, 2026.
What's compelling: A signing key baked into every Issabel installation means one forged token is enough to run OS commands on any unpatched PBX, and exploitation was already observed by the Shadowserver Foundation on September 9, 2026, with no details yet on who is behind it or how far it has spread.

Read the original at The Hacker News ↗

Topics: Vulnerabilities & Patching
Mentions: CVE-2026-89026
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