GHSA-6g43-577r-wf4x

Out-of-Bounds Slice Access in free5GC CHF Leading to DoS

### Impact This is an out-of-bounds slice access vulnerability in the CHF `nchf-convergedcharging` service. A valid authenticated request to PUT `/nchf-convergedcharging/v3/recharging/:ueId?ratingGroup=...` can trigger a server-side panic in `github.com/free5gc/chf/internal/sbi.(*Server).RechargePut(...)` due to an out-of-range slice access. In the reported runtime, Gin recovery converts the panic into HTTP 500, but the recharge path remains remotely panic-triggerable and can be abused repeatedly to degrade recharge functionality and flood logs. In deployments without equivalent recovery handling, this panic may cause more severe service disruption. ### Patches https://github.com/free5gc/chf/pull/61 ### Workarounds - Restrict access to the `nchf-convergedcharging` recharge endpoint to strictly trusted NF callers only. - Apply rate limiting or network ACLs in front of the CHF SBI interface to reduce repeated panic-trigger attempts. - If the recharge API is not required, temporarily disable or block external reachability to this route. - Ensure panic recovery, monitoring, and alerting are enabled.