CVE-2026-64548

In the Linux kernel, the following vulnerability has been resolved:

bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()

When the scatterlist ring is full or nearly full, bpf_msg_push_data() enters a copy fallback path and computes copy + len for the page allocation size. Since len comes from BPF with arg3_type = ARG_ANYTHING and both are u32, a crafted len can wrap the sum to a small value, causing an undersized allocation followed by an out-of-bounds memcpy.

BUG: unable to handle page fault for address: ffffed104089a402 Oops: Oops: 0000 [#1] SMP KASAN NOPTI Call Trace: __asan_memcpy (mm/kasan/shadow.c:105) bpf_msg_push_data (net/core/filter.c:2852 net/core/filter.c:2788) bpf_prog_9ed8b5711920a7d7+0x2e/0x36 sk_psock_msg_verdict (net/core/skmsg.c:934) tcp_bpf_sendmsg (net/ipv4/tcp_bpf.c:421 net/ipv4/tcp_bpf.c:584) __sys_sendto (net/socket.c:2206) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Add an overflow check before the allocation.

This vulnerability is rated as Moderate severity for Red Hat Enterprise Linux because exploitation requires local access with administrative privileges (such as CAP_BPF or CAP_NET_ADMIN) to load and attach BPF socket verdict programs. Standard Red Hat Enterprise Linux configurations restrict eBPF loading to privileged accounts, which significantly limits exposure on typical installations. A privileged attacker could leverage this flaw to cause a kernel crash or corrupt memory through an undersized buffer allocation, but the requirement for elevated capabilities restricts the overall impact.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.