What is CVE-2026-73665?
FreePBX is an open source IP PBX. Prior to 17.0.9, the UCP Node server on ports 8001 and 8003 uses io.use(checkAuth) in node/lib/server.js, but Socket.IO version 4 applies that middleware only to the default namespace. An unauthenticated client can connect to custom namespaces that do not consistently invoke checkAuth in node/lib/auth.js and send crafted event values containing carriage-return or newline characters through the Asterisk Manager Interface action path patched by node/lib/asterisk-manager-patch.js, allowing arbitrary commands to execute as the asterisk service user. This issue is fixed in version 17.0.9.
The record classifies CVE-2026-73665 under weakness class CWE-862. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 53 days ago.
Severity and exploitation probability
- CVSS v4.0 base score
- 9.3 — Critical (derived from score)
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 (FIRST)
- 0.2% probability of exploitation in the next 30 days, higher than 21.9% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-08-13
Is CVE-2026-73665 being exploited?
It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.
Affected products and versions
- FreePBX: ucp
How to fix CVE-2026-73665
No vendor patch reference has been recorded for CVE-2026-73665 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-73665
No threat campaign in the Threadlinqs corpus currently references CVE-2026-73665, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.