CVE-2026-63984 ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()

In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix hdrlen overflow in ipv6rplsrhdecompress ipv6rplsrhdecompress computes: outhdr-hdrlen = n + 1 sizeofstruct in6addr 3; hdrlen is u8. For n = 127 the result exceeds 255 and silently truncates. With n=127 cmpri=15,...