{"cve":"CVE-2021-29441","nvd":{"published":"2021-04-27T21:15:07.993","modified":"2026-06-17T03:47:38.877","status":"Modified","description":"Nacos is a platform designed for dynamic service discovery and configuration and service management. In Nacos before version 1.4.1, when configured to use authentication (-Dnacos.core.auth.enabled=true) Nacos uses the AuthFilter servlet filter to enforce authentication. This filter has a backdoor that enables Nacos servers to bypass this filter and therefore skip authentication checks. This mechanism relies on the user-agent HTTP header so it can be easily spoofed. This issue may allow any user to carry out any administrative tasks on the Nacos server.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-290"],"references":["https://github.com/advisories/GHSA-36hp-jr8h-556f","https://github.com/alibaba/nacos/issues/4701","https://github.com/alibaba/nacos/pull/4703","https://github.com/advisories/GHSA-36hp-jr8h-556f","https://github.com/alibaba/nacos/issues/4701"],"products":["alibaba:nacos"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-29441","score":0.83246,"percentile":0.99679,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-36hp-jr8h-556f","url":"https://osv.dev/vulnerability/GHSA-36hp-jr8h-556f","summary":"Authentication Bypass","modified":"2026-07-08T06:49:40.462036344Z","packages":[{"ecosystem":"Maven","name":"com.alibaba.nacos:nacos-common","purl":"pkg:maven/com.alibaba.nacos/nacos-common","ranges":["<1.4.1"],"fixed":["1.4.1"]}]},{"id":"GHSA-xv5h-v7jh-p2qh","url":"https://osv.dev/vulnerability/GHSA-xv5h-v7jh-p2qh","summary":"Authentication bypass for specific endpoint","modified":"2026-07-08T06:49:40.462036344Z","packages":[{"ecosystem":"Maven","name":"com.alibaba.nacos:nacos-common","purl":"pkg:maven/com.alibaba.nacos/nacos-common","ranges":["<1.4.1"],"fixed":["1.4.1"]}]}],"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."]}