CVE-2026-40247 — udr
CVE-2026-40247 is a CWE-285 vulnerability in github.com/free5gc/udr. No vendor fix is recorded yet; mitigation options are listed below.
free5gc UDR improper path validation allows unauthenticated access to Traffic Influence Subscriptions
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40247.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/free5gc/udrReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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 reading 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 data is returned alongside the 404 response. An unauthenticated attacker with access to the 5G Service Based Interface can read arbitrary Traffic Influence Subscriptions, including SUPIs/IMSIs, DNNs, S-NSSAIs, and callback URIs, by supplying any value for the influenceId path segment. A patched version was not available at the time of publication.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/free5gc/udr | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/free5gc/udr, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of github.com/free5gc/udr has shipped for CVE-2026-40247 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40247 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-40247. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40247 in your dependencies?
O3 Security finds CVE-2026-40247 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.