{"cve":"CVE-2020-26276","nvd":{"published":"2020-12-17T20:15:13.760","modified":"2026-06-17T03:07:58.797","status":"Modified","description":"Fleet is an open source osquery manager. In Fleet before version 3.5.1, due 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. Users that configure Fleet with SSO login may be vulnerable to this issue. This issue is patched in 3.5.1. The fix was made using https://github.com/mattermost/xml-roundtrip-validator If upgrade to 3.5.1 is not possible, users should disable SSO authentication in Fleet.","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/fleetdm/fleet/blob/master/CHANGELOG.md#fleet-351-dec-14-2020","https://github.com/fleetdm/fleet/commit/57812a532e5f749c8e18c6f6a652eca65c083607","https://github.com/fleetdm/fleet/security/advisories/GHSA-w3wf-cfx3-6gcx","https://github.com/mattermost/xml-roundtrip-validator","https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities"],"products":["fleetdm:fleet"],"source":"nvd","synced_at":"2026-10-19T21:12:09.559580076+00:00"},"epss":{"cve":"CVE-2020-26276","score":0.02195,"percentile":0.82473,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-w3wf-cfx3-6gcx","url":"https://osv.dev/vulnerability/GHSA-w3wf-cfx3-6gcx","summary":"SAML authentication vulnerability due to stdlib XML parsing","modified":"2026-09-10T03:49:12.818096744Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","ranges":["<3.5.1"],"fixed":["3.5.1"]}]}],"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."]}