[github.com/free5gc/free5gc] free5GC vulnerable to malformed NGAP message crashing the AMF and NGAP decoders

In free5GC 3.2.1, a malformed NGAP message can crash the AMF and NGAP decoders via an index-out-of-range panic in aper.GetBitString.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-43677
• https://github.com/free5gc/free5gc/issues/402
• https://github.com/advisories/GHSA-59hj-62f5-fgmc