CVE-2026-40249 — free5gc UDR fail-open request handling in PolicyDataSubsToNotifySubsIdPut may allow unintended subscription updates after input errors
free5GC is an open-source implementation of the 5G core network. In versions 4.2.1 and below of the UDR service, the PUT handler for updating Policy Data notification subscripti…
Published: 2026-04-16 · CVSS: 6.9 · CVSS 4.0
free5GC is an open-source implementation of the 5G core network. In versions 4.2.1 and below of the UDR service, the PUT handler for updating Policy Data notification subscriptions at /nudr-dr/v2/policy-data/subs-to-notify/{subsId} does not return after request body retrieval or deserialization errors. Although HTTP 500 or 400 error responses are sent, execution continues and the processor is invoked with a potentially uninitialized or partially initialized PolicyDataSubscription object. This fail-open behavior may allow unintended modification of existing Policy Data notification subscriptions with invalid or empty input, depending on downstream processor and storage behavior. A patched version was not available at the time of publication.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7