CVE-2021-27860

CVE-2021-27860 is an unrestricted file upload flaw (CWE-434) in the web management interface of FatPipe WARP, IPVPN, and MPVPN appliances, allowing a remote, unauthenticated attacker to upload a file to any location on the device's filesystem. It is triggered simply by sending an upload request to the exposed management interface, with no credentials required. An attacker who abuses it can place files anywhere on the appliance, which can be used to tamper with device configurations or plant files that may enable further compromise or code execution. Any organization running an internet-exposed FatPipe WARP, IPVPN, or MPVPN device — typically deployed as edge/SD-WAN and WAN failover appliances at enterprise and branch sites — is affected. The flaw is confirmed exploited in the wild (added to CISA KEV on 2022-01-10), carries a high EPSS of 39.8% (99th percentile) for near-term exploitation, and while no public PoC is known, ransomware involvement is listed as unknown.

What to do: Apply updates per vendor instructions, as required by CISA's KEV listing, since no specific fixed version numbers are provided in this data. In the interim, restrict access to the FatPipe web management interface with firewall rules or ACLs so it is not reachable from the internet. Check exposed devices for unexpected or recently modified files and configuration changes, given the unknown possibility of ransomware-related abuse.