free5GC NRF Discovery EncodeGroupId Function Panics on Malformed group-id-list Parameter

Impact
This is an Improper Input Validation vulnerability leading to Denial of Service.

• Security Impact: A remote attacker can cause the NRF service to panic and crash by sending a crafted HTTP GET request with a malformed group-id-list parameter. This results in complete denial of service for the NRF discovery service.
• Functional Impact: The EncodeGroupId function attempts to access array indices [0], [1], [2] without validating the length of the split data. When the parameter contains insufficient separator characters, the code panics with "index out of range".
• Affected Parties: All deployments of free5GC v4.0.1 using the NRF discovery service.

Patches
Yes, the issue has been patched.
The fix is implemented in PR free5gc/nrf#80 (commit: [add fix reference here]).
Users should upgrade to the next release of free5GC that includes this commit.

Workarounds
There is no direct workaround at the application level. The recommendation is to apply the provided patch or restrict access to the NRF API to trusted sources only.