CVE-2026-40245 Free5GC: UDR nudr-dr influenceData/subs-to-notify leaks SUPI in error response body without authentication
Unauthenticated attackers can retrieve sensitive subscriber identifiers (SUPI/IMSI) from Free5GC UDR service via a parameterless HTTP GET request due to missing error handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40245?
CVE-2026-40245 is a high-severity vulnerability in Free5gc Free5gc, published on 15 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-40245?
3 open source packages ship an affected version, including github.com/free5gc/udr. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/free5gc/udr Go | All versions | None |
github.com/free5gc/udr Go | All versions to 1.4.2 | None |
github.com/free5gc/udr Go | All versions to 1.4.2 | None |
Products include Free5gc Free5gc.
How do I fix CVE-2026-40245?
Upgrade to a fixed version.
Is CVE-2026-40245 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40245 exists.
Other vulnerabilities in Free5gc Free5gc
- CVE-2026-44327 free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
- CVE-2026-44329 free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers
- CVE-2026-44330 free5GC's NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions
- CVE-2025-63679 Memory corruption in n/a
- CVE-2026-44315 free5GC's NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create, read, and delete PFD transactions
Sources
Also known as GHSA-wrwh-rpq4-87hf, GO-2026-5722.