Cisco patches Nexus, IOS XR, IP Phone flaws

CERT-FR advisory details multiple Cisco vulnerabilities allowing remote code execution, denial of service, and security bypass across Nexus 9000, IOS XR, and IP Phone products.

CERT-FR published an advisory (CERTFR-2026-AVI-1110) covering multiple vulnerabilities in Cisco products, referencing three separate Cisco security bulletins issued on 2 September 2026. Affected systems include Cisco Nexus 9000 Series Switches with Silicon One ASIC, numerous IOS XR Software Train versions (ranging from 6.9.x through 26.3.x), and SIP Software used in several IP Phone models including Wireless IP Phone 8821, IP Phone 7800/8800 Series, IP Phone 8845/8865, Desk Phone 9800 Series, and Video Phone 8875.

The vulnerabilities collectively allow an attacker to achieve remote arbitrary code execution, remote denial of service, and bypass of security policy, though the vector (remote/local, authenticated/unauthenticated) is not specified in the advisory itself. Nine CVEs are referenced (CVE-2026-20212, 20274-20281). No indication of active exploitation in the wild is given; the advisory is a standard vendor patch notification distributed by CERT-FR. Defenders operating affected Cisco Nexus 9000 switches, IOS XR routers, or the listed Cisco IP/desk phone models should consult the linked Cisco security bulletins and apply the specified fixed releases or latest security patches.

Given the breadth of affected products (core switching/routing infrastructure and endpoint telephony) and the potential for remote code execution and denial of service, organizations running Cisco networking gear should prioritize patching per Cisco's guidance, particularly for internet-facing or critical infrastructure deployments of IOS XR and Nexus 9000 devices.

Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-1110