{"id":"CVE-2026-40249","aliases":["GHSA-gx38-8h33-pmxr","GO-2026-5407"],"url":"https://o3.security/vulnerability/CVE-2026-40249","summary":"free5gc UDR fail-open request handling in PolicyDataSubsToNotifySubsIdPut may allow unintended subscription updates after input errors","details":"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.","published":"2026-04-16T21:59:36.282Z","modified":"2026-09-04T03:46:51.742708950Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/free5gc/udr","fixedVersion":null}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40249.json"},{"type":"ADVISORY","url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-gx38-8h33-pmxr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40249"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-04T03:46:51.742708950Z"}}