In the Linux kernel, the following vulnerability has been resolved: bpf: Fix overflow of jump offset in constant blinding bpf_jit_blind_insn()… (CVE-2026-98816)

The vulnerability involves the bpf_jit_blind_insn() function in the Linux kernel, which rewrites conditional jump instructions by blinding constants. When the jump offset (off) is negative and near the lower bound of a signed 16-bit integer (s16), subtracting 2 causes an integer overflow, wrapping the jump offset to a large positive value. This results in the jump going beyond the end of the BPF program. The kernel's branch adjustment function bpf_adj_branches() does not check this overflow because the jump is modified inside the patch. Consequently, running such a BPF program with bpf_jit_harden=2 causes a kernel crash. The fix returns an -ERANGE error when such an overflow would occur, preventing the crash. The related function bpf_jit_blind_constants() has a similar issue when blinding other instructions that move jumps out of range.

The vulnerability can cause the Linux kernel to crash (kernel panic) when executing specially crafted BPF programs with the bpf_jit_harden=2 setting enabled. This results in a denial of service condition. There is no indication of code execution or privilege escalation from the provided data.

A fix has been implemented in the Linux kernel to return an error (-ERANGE) when the jump offset overflow condition is detected, preventing the kernel crash. Users should update to the fixed kernel version once available. No additional mitigation steps are indicated.