{"id":"CVE-2018-21246","aliases":["EUVD-2022-7098","GHSA-gr7w-x2jp-3xgw","GO-2020-0043"],"status":"published","title":"Caddy vulnerable to Authentication Bypass due to mishandling of TLS client authentication","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.02723,"percentile":0.8615,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-287"],"published":"2020-06-15T16:50:25Z","modified":"2026-10-20T10:48:03Z","fixes":[{"ecosystem":"Go","package":"github.com/caddyserver/caddy","fixed_in":["0.10.13"],"sources":["ghsa","osv"]},{"ecosystem":"Go","package":"github.com/mholt/caddy","fixed_in":["0.10.13"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/caddyserver/caddy","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.10.13"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/caddyserver/caddy","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.10.13"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/mholt/caddy","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.10.13"}]}]}],"products":[{"vendor":"caddyserver","product":"caddy"}],"references":[{"url":"https://github.com/caddyserver/caddy/releases/tag/v0.10.13","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","advisory","web"]},{"url":"https://bugs.gentoo.org/715214","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-21246","tags":["advisory"]},{"url":"https://github.com/caddyserver/caddy/commit/4d9ee000c8d2cbcdd8284007c1e0f2da7bc3c7c3","tags":["web","fix"]},{"url":"https://github.com/caddyserver/caddy/pull/2099","tags":["web","fix"]},{"url":"https://pkg.go.dev/vuln/GO-2020-0043","tags":["web"]},{"url":"https://github.com/advisories/GHSA-gr7w-x2jp-3xgw"},{"url":"https://github.com/caddyserver/caddy","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2018-21246","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","status":"published","published":"2020-06-15T16:50:25Z","modified":"2024-08-05T12:26:39.466Z","updated_at":"2026-11-02T14:35:02.289647Z"}],"euvd":[{"id":"EUVD-2022-7098","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","status":"published","published":"2020-06-15T16:50:25Z","modified":"2024-08-05T12:26:39Z","updated_at":"2026-11-03T02:39:27.400094Z"}],"ghsa":[{"id":"GHSA-gr7w-x2jp-3xgw","title":"Caddy vulnerable to Authentication Bypass due to mishandling of TLS client authentication","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","status":"published","published":"2022-10-06T22:58:56Z","modified":"2023-02-14T20:47:17Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:36:45.67005Z"}],"nvd":[{"id":"CVE-2018-21246","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","status":"published","published":"2020-06-15T17:15:09.62Z","modified":"2026-06-17T01:54:27.76Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:05:00.03074Z"}],"osv":[{"id":"CVE-2018-21246","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","status":"published","published":"2020-06-15T17:15:09.62Z","modified":"2026-10-20T10:48:03.754559131Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:44:09.145458Z"},{"id":"GHSA-gr7w-x2jp-3xgw","title":"Caddy vulnerable to Authentication Bypass due to mishandling of TLS client authentication","description":"Caddy before 0.10.13 mishandles TLS client authentication, as demonstrated by an authentication bypass caused by the lack of the StrictHostMatching mode.","status":"published","published":"2022-10-06T22:58:56Z","modified":"2023-11-08T04:00:14.482973Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T15:46:48.191583Z"},{"id":"GO-2020-0043","title":"Authentication bypass in github.com/mholt/caddy","description":"Due to improper TLS verification when serving traffic for multiple SNIs, an attacker may bypass TLS client authentication by indicating an SNI during the TLS handshake that is different from the name in the HTTP Host header.","status":"published","published":"2021-04-14T20:04:52Z","modified":"2024-05-20T16:03:47Z","updated_at":"2026-11-02T15:47:00.604718Z"}]}}