{"id":"GHSA-w3wf-cfx3-6gcx","summary":"SAML authentication vulnerability due to stdlib XML parsing","details":"### Impact\nDue to issues in Go's standard library XML parsing, a valid SAML response may be mutated by an attacker to modify the trusted document. This can result in allowing unverified logins from a SAML IdP.\n\nUsers that configure Fleet with SSO login may be vulnerable to this issue.\n\n### Patches\nThis issue is patched in 3.5.1 using https://github.com/mattermost/xml-roundtrip-validator.\n\n### Workarounds\nIf upgrade to 3.5.1 is not possible, users should disable SSO authentication in Fleet.\n\n### References\nSee https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities/ for more information about the underlying vulnerabilities.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at [security@fleetdm.com](mailto:security@fleetdm.com)\n* Join #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)","aliases":["CVE-2020-26276"],"modified":"2026-05-07T05:03:02.577476710Z","published":"2022-02-11T23:59:14Z","database_specific":{"github_reviewed_at":"2021-05-21T20:46:21Z","nvd_published_at":"2020-12-17T20:15:00Z","cwe_ids":["CWE-290"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/fleetdm/fleet/security/advisories/GHSA-w3wf-cfx3-6gcx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-26276"},{"type":"WEB","url":"https://github.com/fleetdm/fleet/commit/57812a532e5f749c8e18c6f6a652eca65c083607"},{"type":"WEB","url":"https://github.com/fleetdm/fleet/blob/master/CHANGELOG.md#fleet-351-dec-14-2020"},{"type":"WEB","url":"https://github.com/mattermost/xml-roundtrip-validator"},{"type":"WEB","url":"https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities"}],"affected":[{"package":{"name":"github.com/fleetdm/fleet/v4","ecosystem":"Go","purl":"pkg:golang/github.com/fleetdm/fleet/v4"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.5.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/02/GHSA-w3wf-cfx3-6gcx/GHSA-w3wf-cfx3-6gcx.json"}}],"schema_version":"1.9.0"}