A flaw exists in the Open5GS NSSF component within the function nssf_nnrf_nsselection_handle_get_from_amf_or_vnssf that allows an attacker to send a crafted request and trigger a crash, leading to a loss of availability for the network element. The vulnerability is explicitly stated as a denial of service and the exploit can be performed remotely. The description confirms that an exploit has already been published and may be used in the wild.

Versions of Open5GS up to and including 2.7.7 contain the vulnerable NSSF module. Systems running these builds are directly impacted, while newer releases are presumed to contain the fix although no official confirmation is provided.

The CVSS score of 5.3 indicates moderate severity. The EPSS score is not available, providing no quantified probability of exploitation. The vulnerability is not listed in CISA’s KEV catalog. Because the attack vector is remote, an adversary only needs network access to the NSSF service to trigger a denial of service. The publicly available exploit raises the risk of real‑world attacks.