ASR Lapwing Linux CVE-2026-42800

Consult the ASR Product Security Incident Response Team (PSIRT) advisory at https://www.asrmicro.com/en/goods/psirt?cid=44 for vendor-released patches or firmware updates for ASR1903 devices running Lapwing Linux. Exact fixed version not confirmed from available data-verify current patch status directly with ASR support. If patches are unavailable or cannot be immediately applied, implement these compensating controls: restrict network access to IMS client interfaces using firewall rules to trusted SIP trunks and authenticated peers only, reducing exposure to low-trust networks; disable IMS/VoIP functionality entirely on ASR1903 devices if not operationally required, eliminating the attack surface; implement strict authentication controls and monitor for suspicious SIP INVITE/REGISTER traffic patterns targeting the ims_client service; deploy network-based SIP application layer gateways to validate and sanitize SIP URIs before they reach vulnerable ASR devices, though this adds latency and complexity to VoIP call flows. Trade-offs: Disabling IMS breaks telephony features. Network filtering may block legitimate but non-standard SIP URI formats. Application gateways introduce single points of failure.