{"cve":"CVE-2026-44320","nvd":{"published":"2026-05-27T17:16:37.177","modified":"2026-10-14T20:10:00.190","status":"Analyzed","description":"free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-callback route group without inbound OAuth2/bearer-token authorization. A forged or arbitrary bearer token (e.g. Authorization: Bearer not-a-real-token) is enough to reach the SMF-callback handler -- the callback body is parsed and dispatched into NEF business logic instead of being rejected at the auth boundary. Same root cause as the other NEF SBI findings: the route group is mounted without any inbound auth middleware. NEF does not authenticate the producer NF identity before processing callback content; if an attacker can guess or obtain a valid NotifId, this missing auth boundary lets forged callbacks act on real subscription state. The route group is also reachable even when the runtime ServiceList does not declare it (it lists only nnef-pfdmanagement and nnef-oam). This vulnerability is fixed in 4.2.2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L","score":7.3},"cwes":["CWE-306","CWE-862"],"references":["https://github.com/free5gc/free5gc/issues/860","https://github.com/free5gc/free5gc/security/advisories/GHSA-wqfh-gq79-j8mf","https://github.com/free5gc/nef/pull/24","https://github.com/free5gc/free5gc/security/advisories/GHSA-wqfh-gq79-j8mf"],"products":["free5gc:free5gc"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-44320","score":0.00241,"percentile":0.1504,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-wqfh-gq79-j8mf","url":"https://osv.dev/vulnerability/GHSA-wqfh-gq79-j8mf","summary":"free5GC's NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path","modified":"2026-06-25T23:11:41.845125863Z","packages":[{"ecosystem":"Go","name":"github.com/free5gc/nef","purl":"pkg:golang/github.com/free5gc/nef","ranges":["<=1.2.3"],"fixed":[]}]},{"id":"GO-2026-5717","url":"https://osv.dev/vulnerability/GO-2026-5717","summary":"free5GC's NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path in github.com/free5gc/nef","modified":"2026-06-25T23:01:28.028915977Z","packages":[{"ecosystem":"Go","name":"github.com/free5gc/nef","purl":"pkg:golang/github.com/free5gc/nef","ranges":["all versions"],"fixed":[]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}