The vulnerability resides in the UDR component of Open5GS, in the function ogs_dbi_subscription_data located in lib/dbi/subscription.c. An attacker can manipulate the argument supi_id to cause a denial‑of‑service condition, disabling the UDR service. The impact is a loss of availability; there is no direct compromise of confidentiality or integrity. This weakness is classified as CWE‑404, reflecting a lack of proper validation or error handling for incoming data.

The affected product is Open5GS, specifically the UDR component. All releases up to and including version 2.7.7 are vulnerable. No later version is documented as fixing the issue, so any deployment of Open5GS 2.7.7 or earlier that relies on the UDR service is potentially impacted.

The CVSS score of 5.3 indicates medium severity. The EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog, suggesting that exploitation may not yet be widespread. Nonetheless, the attack can be performed remotely against any UDR instance exposing the subscription endpoint and accepting externally supplied supi_id values. Until an official patch is released, the risk remains for environments running the affected Open5GS versions.