CVE-2026-40245: Free5GC: UDR nudr-dr influenceData/subs-to-notify leaks SUPI in error response body without authentication

Vulnerability summary

CVE-2026-40245 is a high (CVSS 7.5) vulnerability in free5gc. EPSS estimates a 0.56% chance of exploitation in the next 30 days, higher than 46.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-04-2026
   PublishedVulnerability first disclosed.
2. 16-04-2026
   Last modifiedVulnerability information updated.

Description

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions 4.2.1 and below contain an information disclosure vulnerability in the UDR (Unified Data Repository) service. The handler for GET /nudr-dr/v2/application-data/influenceData/subs-to-notify sends an HTTP 400 error response when required query parameters are missing but does not return afterward. Execution continues into the processor function, which queries the data repository and appends the full list of Traffic Influence Subscriptions, including SUPI/IMSI values, to the response body. An unauthenticated attacker with network access to the 5G Service Based Interface can retrieve stored subscriber identifiers with a single parameterless HTTP GET request. The SUPI is the most sensitive subscriber identifier in 5G networks, and its exposure undermines the privacy guarantees of the 3GPP SUCI concealment mechanism at the core network level. A similar bypass exists when sending a malformed snssai parameter due to the same missing return pattern.

• CWE-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
• CWE-202Exposure of Sensitive Information Through Data QueriesWhen trying to keep information confidential, an attacker can often infer some of the information by using statistics.
• CWE-209Generation of Error Message Containing Sensitive InformationThe product generates an error message that includes sensitive information about its environment, users, or associated data.