Jianguo Wu

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** The issue is related to the Linux kernel's seg6 module, where the `input action end dx4()` and `input action end dx6()` functions are called with `NF HOOK()` for the PREROUTING hook. In this hook, a valid `indev` and a NULL `outdev` should be passed to `NF HOOK()`. However, if a NULL `indev` is passed, it may trigger a NULL pointer dereference. This can occur when `input action end dx4()` passes a NULL `indev` to `NF HOOK()`, which can then trigger a NULL dereference in `rpfilter mt()->rpfilter is loopback()`. The `rpfilter is loopback()` function checks if a packet is a loopback packet or if the input device has the `IFF LOOPBACK` flag set. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.