CVE-2026-40248 free5gc UDR improper path validation allows unauthenticated creation and modification of Traffic Influence Subscriptions
Unauthenticated attackers can create or modify Traffic Influence Subscriptions in free5GC UDR due to improper path validation, allowing injection of malicious notification URIs and SUPIs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40248?
CVE-2026-40248 is a high-severity missing authorization vulnerability in Free5gc Free5gc, published on 16 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 implementation of the 5G core network. In versions 4.2.1 and below of the UDR service, the handler for creating or updating Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending the HTTP 404 response when validation fails. Execution continues and the subscription is created or overwritten regardless. An unauthenticated attacker with access to the 5G Service Based Interface can create or overwrite arbitrary Traffic Influence Subscriptions, including injecting attacker-controlled notificationUri values and arbitrary SUPIs, by supplying any value for the influenceId path segment. A patched version was not available at the time of publication.
Which versions are affected by CVE-2026-40248?
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-2026-40248?
No fix published yet.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-40248 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40248 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-jgq2-qv8v-5cmj, GO-2026-5470.