{"id":"GHSA-m697-4v8f-55qg","summary":"Header dropping in traefik","details":"# Impact\n\nThere exists a potential header vulnerability in Traefik's handling of the Connection header. Active exploitation of this issue is unlikely, as it requires that a removed header would lead to a privilege escalation, however, the Traefik team has addressed this issue to prevent any potential abuse.\n\n# Details\n\nIf you have a chain of Traefik middlewares, and one of them sets a request header `Important-Security-Header`, then sending a request with the following Connection header will cause it to be removed before the request was sent:\n\n```\ncurl 'https://example.com' -H \"Connection: Important-Security-Header\" -0\n```\n\nIn this case, the backend does not see the request header `Important-Security-Header`.\n\n# Patches\n\nTraefik v2.4.x: https://github.com/traefik/traefik/releases/tag/v2.4.13\n\n# Workarounds\n\nNo.\n\n# For more information\n\nIf you have any questions or comments about this advisory, [open an issue](https://github.com/traefik/traefik/issues).\n","aliases":["CVE-2021-32813","GO-2022-0923"],"modified":"2026-07-08T06:29:38.204785391Z","published":"2021-08-05T17:04:21Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2021-08-04T18:54:19Z","nvd_published_at":"2021-08-03T23:15:00Z","cwe_ids":["CWE-913"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/traefik/traefik/security/advisories/GHSA-m697-4v8f-55qg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32813"},{"type":"WEB","url":"https://github.com/traefik/traefik/pull/8319/commits/cbaf86a93014a969b8accf39301932c17d0d73f9"},{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v2.4.13"},{"type":"PACKAGE","url":"github.com/traefik/traefik"}],"affected":[{"package":{"name":"github.com/traefik/traefik/v2","ecosystem":"Go","purl":"pkg:golang/github.com/traefik/traefik/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.4.13"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/08/GHSA-m697-4v8f-55qg/GHSA-m697-4v8f-55qg.json"}},{"package":{"name":"github.com/traefik/traefik","ecosystem":"Go","purl":"pkg:golang/github.com/traefik/traefik"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"1.7.30"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/08/GHSA-m697-4v8f-55qg/GHSA-m697-4v8f-55qg.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}