{"id":"CVE-2026-40249","state":"PUBLISHED","title":"free5gc UDR fail-open request handling in PolicyDataSubsToNotifySubsIdPut may allow unintended subscription updates after input errors","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.","publishedAt":"2026-04-16T21:59:36.282Z","updatedAt":"2026-04-18T02:47:28.094Z","severity":{"score":6.9,"label":"Medium","version":"4.0","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","source":"GitHub_M"},"assigner":"GitHub_M","products":["free5gc free5gc"],"affected":[{"vendor":"free5gc","product":"free5gc","versions":[{"version":"<= 4.2.1","status":"affected"}]}],"references":["https://github.com/free5gc/free5gc/security/advisories/GHSA-gx38-8h33-pmxr"],"weaknesses":["CWE-754","CWE-636"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/40xxx/CVE-2026-40249.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-40249","state":"PUBLISHED","datePublished":"2026-04-16T21:59:36.282Z","dateUpdated":"2026-04-18T02:47:28.094Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-10T17:31:45.786Z"},"containers":{"cna":{"title":"free5gc UDR fail-open request handling in PolicyDataSubsToNotifySubsIdPut may allow unintended subscription updates after input errors","descriptions":[{"lang":"en","value":"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":[{"vendor":"free5gc","product":"free5gc","versions":[{"version":"<= 4.2.1","status":"affected"}]}],"references":[{"url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-gx38-8h33-pmxr","name":"https://github.com/free5gc/free5gc/security/advisories/GHSA-gx38-8h33-pmxr","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-754","lang":"en","description":"CWE-754: Improper Check for Unusual or Exceptional Conditions","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-636","lang":"en","description":"CWE-636: Not Failing Securely ('Failing Open')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-16T21:59:36.282Z"},"source":{"advisory":"GHSA-gx38-8h33-pmxr","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-18T02:47:14.512033Z","id":"CVE-2026-40249","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-18T02:47:28.094Z"}}]}}}