In the Linux kernel, the following vulnerability has been resolved: bpf: Keep dynamic inner array lookups nullable An ARRAY_OF_MAPS can use an array created with BPF_F_INNER_MAP as its inner map template. A concrete inner array with a different max_entries value can then replace the template. After a successful outer map lookup, the verifier represents the resulting map pointer using the inner map template. Const-key lookup nullness elision consequently uses the template max_entries even though the runtime helper uses the concrete inner map max_entries. Do not elide lookup result nullness for maps marked with BPF_F_INNER_MAP, because the template max_entries does not prove that the key is in bounds for the concrete runtime map.
https://git.kernel.org/stable/c/d57db0d975053e01410c54e708a85b6d32ef2ebd
https://git.kernel.org/stable/c/53040a81ae57cdca8af8ac36fe4e661730cf7c6b
https://git.kernel.org/stable/c/0b92ad64d6e4bde85e6b9888404f9a7a2b65d269