free5gc UDR improper path validation allows unauthenticated access to Traffic Influence Subscriptions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-40247: 0.49% estimated exploitation activity in the next 30 days; percentile 42.38 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary An improper path validation vulnerability in the UDR service allows any unauthenticated attacker with access to the 5G Service Based Interface (SBI) to read Traffic Influence Subscriptions by supplying an arbitrary value in place of the expected subs-to-notify path segment. Details The endpoint GET /nudr-dr/v2/application-data/influenceData/{influenceId}/{subscriptionId} is intended to only operate on Traffic Influence Subscription resources when influenceId is exactly subs-to-notify. In the free5GC UDR implementation, the path validation is present but ineffective because the handler does not return after sending the HTTP 404 response. The request handling flow is: 1. The function HandleApplicationDataInfluenceDataSubsToNotifySubscriptionIdGet in ./free5gc4-2-1/free5gc/NFs/udr/internal/sbi/apidatarepository.go checks whether influenceId != "subs-to-notify". 2. If the value is different, it calls c.String(http.StatusNotFound, "404 page not found"), but it does not return…

Published by the source

14 Apr 2026, 20:00 UTC

Last modified by the source

24 Apr 2026, 20:36 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-x5r2-r74c-3w28

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# Patch Next advisory brief: CVE-2026-40247

Advisory: free5gc UDR improper path validation allows unauthenticated access to Traffic Influence Subscriptions
IDs: CVE-2026-40247, GHSA-x5r2-r74c-3w28
Record: https://patchnext.com/advisories/cve-2026-40247 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/udr: affected <= 1.4.2

## Suggested inspection (read-only)
- Go github.com/free5gc/udr: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/free5gc/udr.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-x5r2-r74c-3w28 (GitHub-reviewed advisory GHSA-x5r2-r74c-3w28 lists affected ranges: Go github.com/free5gc/udr >=0 <=1.4.2)

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