Vulnerabilities in Node.js and Brotli Affecting Cisco Products: October 2026
cisco-sa-oct2026-node-js-Jj3SQ19u
Summary
A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary commands as root on an affected device. This vulnerability is due to insecure deserialization of a user-supplied Java byte stream from a host that is configured in the external database access list.
An attacker could exploit this vulnerability by sending a crafted, serialized Java byte stream to a specific TCP port of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the device and elevate privileges to root. Notes: This vulnerability can be exploited only by an attacker who has control of a host in the external database access list.
If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of September 16, 2026, Security Advisories.
In addition, for further documentation of improvements and fixes in Cisco Secure Firewall products, see Cisco Secure Firewall Adaptive Security Appliance Software, Secure Firewall Threat Defense Software, and Secure Firewall Management Center Software Hardening Release: September 2026. Security Impact Rating: Critical CVE: CVE-2026-20242
Products covered
A separate affected-products list was not included in the collected bulletin.
Remediation
Cisco has released software updates that address this vulnerability.
CVEs in this advisory 1
Update history
What changed in later vendor updates
SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.
- The vendor changed the advisory summary.
Updates
- Published by Cisco
The publication date reported by the vendor.
- Added to SecurityAlert
We collected the advisory from the official source.
- Confirmed at the source
Our collector saw this advisory during a later source check.