Vulnerability · Published Apr 16, 2026 · Assigned by GitHub_M
CVE-2026-40249free5gc UDR fail-open request handling in PolicyDataSubsToNotifySubsIdPut may allow unintended subscription updates after input errors
Medium 6.9
In plain English
A medium-severity security flaw in free5gc from free5gc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities).
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 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/free5gc/udr | no fix listed | GHSA-gx38-8h33-pmxr |
| Go | github.com/free5gc/udr | no fix listed | GO-2026-5407 |
Affected products (as reported)
Weakness: CWE-754, CWE-636 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/free5gc/free5gc/security/advisories/GHSA-gx38-8h33-pmxr x_refsource_CONFIRM