CVE-2026-53036

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf, arm64: Fix off-by-one in check_imm signed range check<br /> <br /> check_imm(bits, imm) is used in the arm64 BPF JIT to verify that<br /> a branch displacement (in arm64 instruction units) fits into the<br /> signed N-bit immediate field of a B, B.cond or CBZ/CBNZ encoding<br /> before it is handed to the encoder. The macro currently tests for<br /> (imm &gt; 0 &amp;&amp; imm &gt;&gt; bits) || (imm &gt; bits) which admits<br /> values in [-2^N, 2^N) — effectively a signed (N+1)-bit range. A<br /> signed N-bit field only holds [-2^(N-1), 2^(N-1)), so the check<br /> admits one extra bit of range on each side.<br /> <br /> In particular, for check_imm19(), values in [2^18, 2^19) slip past<br /> the check but do not fit into the 19-bit signed imm19 field of<br /> B.cond. aarch64_insn_encode_immediate() then masks the raw value<br /> into the 19-bit field, setting bit 18 (the sign bit) and flipping<br /> a forward branch into a backward one. Same class of issue exists<br /> for check_imm26() and the B/BL encoding. Shift by (bits - 1)<br /> instead of bits so the actual signed N-bit range is enforced.