{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-56020: Webmin HTTP header authentication bypass","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-56020","status":"final","version":"1","initial_release_date":"2026-06-18T16:12:05.368Z","current_release_date":"2026-06-18T16:12:05.368Z","revision_history":[{"date":"2026-06-18T16:12:05.368Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.641.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-56020 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-56020"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-56020"},{"category":"external","summary":"url","url":"https://github.com/webmin/webmin/releases/tag/2.641"},{"category":"external","summary":"url","url":"https://webmin.com/security/#webmin-prior-to-2641"},{"category":"external","summary":"url","url":"https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json"},{"category":"external","summary":"url","url":"https://www.cve.org/CVERecord?id=CVE-2026-56020"}]},"product_tree":{"branches":[{"category":"vendor","name":"Webmin","branches":[{"category":"product_name","name":"Webmin","branches":[{"category":"product_version_range","name":"<2.641","product":{"name":"Webmin Webmin <2.641","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:webmin:webmin:*:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"2.641","product":{"name":"Webmin Webmin 2.641","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:webmin:webmin:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-56020","title":"Webmin HTTP header authentication bypass","notes":[{"category":"description","text":"The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.641.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"],"fixed":["CSAFPID-2"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","baseScore":9.2,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 2.641.","product_ids":["CSAFPID-1"]}]}]}