Double Free in Treck TCP/IP Stack IPv4 Tunneling

Successful exploitation may allow a remote, unauthenticated attacker to corrupt memory in the affected device's networking stack, potentially causing a use-after-free condition. Based on the supplied advisory context for Ripple20, exploitation of Treck stack flaws may result in denial of service, information disclosure, or arbitrary code execution depending on the specific implementation and deployment. For CVE-2020-11900 specifically, the confirmed direct consequence in the provided content is use-after-free arising from a double free in IPv4 tunneling packet handling.

If immediate patching is not possible, reduce exposure of affected devices and limit attacker reachability to the vulnerable IPv4 tunneling functionality. The provided advisory guidance recommends network segmentation, minimizing internet exposure, blocking anomalous IP traffic, normalizing or rejecting IP fragments, disabling unused features such as IP tunneling and source routing where feasible, enforcing TCP inspection, blocking unused ICMP messages, using secure DNS and DHCP configurations, and deploying IDS/IPS detections for exploitation attempts. Downstream users should also contact device vendors for product-specific mitigations.

Upgrade the Treck TCP/IP stack to a fixed release. The vulnerability description states affected versions are before 6.0.1.41, while the broader Ripple20 remediation guidance in the provided content recommends updating to Treck IP stack version 6.0.1.67 or later, or applying vendor-provided patches for affected downstream products. Because Treck is commonly embedded by OEMs, operators should obtain and apply the relevant firmware or software update from the device manufacturer where direct stack updates are not possible.