CVE-2025-38463 is a Linux kernel vulnerability involving incorrect signedness handling in the calculation of remaining space in socket buffers (skb) during TCP data transmission. This flaw can cause an integer overflow in the sk_forward_alloc field, potentially leading to memory allocation errors and denial of service. The issue arises when the subtraction of skb length from a size goal is incorrectly handled due to type promotion rules, resulting in a large positive value instead of a negative one. The vulnerability was reported by Syzkaller and can be triggered using TCP_REPAIR or occur naturally in certain TCP memory scheduling scenarios.