Use-After-Free Vulnerability in Linux Kernel's GTP Module

CVE-2026-89789

What is CVE-2026-89789?

A vulnerability in the Linux kernel's GTP (GPRS Tunneling Protocol) module has been identified, where improper synchronization may lead to a use-after-free scenario. Specifically, in the gtp_newlink() function, tid_hash and addr_hash are freed without ensuring that the RCU (Read-Copy Update) grace period has elapsed after clearing sk_user_data. This could result in concurrent access to freed memory by gtp_encap_recv(), leading to potential system instability and security risks. To enhance memory safety, it is critical to implement synchronize_net() calls prior to memory deallocation, addressing all error paths from both gtp_encap_enable() and gtp_create_sockets() functions.

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