net/igmpproxy: Fix buffer overflow and use after free
Taken from upstream pull requests:
https://github.com/pali/igmpproxy/pull/98
https://github.com/pali/igmpproxy/pull/99
PR: 291642
MFH: 2025Q4
(cherry picked from commit a0bac3ef72b259e93cafefe1c39e146bbe23fce2)