{"cve":"CVE-2021-31999","nvd":{"published":"2021-07-15T09:15:08.210","modified":"2026-06-17T03:52:39.060","status":"Modified","description":"A Reliance on Untrusted Inputs in a Security Decision vulnerability in Rancher allows users in the cluster to act as others users in the cluster by forging the \"Impersonate-User\" or \"Impersonate-Group\" headers. This issue affects: Rancher versions prior to 2.5.9. Rancher versions prior to 2.4.16.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-807"],"references":["https://bugzilla.suse.com/show_bug.cgi?id=1187084","https://bugzilla.suse.com/show_bug.cgi?id=1187084"],"products":["rancher:rancher"],"source":"nvd","synced_at":"2026-10-19T21:21:13.713336758+00:00"},"epss":{"cve":"CVE-2021-31999","score":0.01052,"percentile":0.64355,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-pvxj-25m6-7vqr","url":"https://osv.dev/vulnerability/GHSA-pvxj-25m6-7vqr","summary":"Rancher Privilege escalation vulnerability via malicious \"Connection\" header","modified":"2026-09-10T03:50:12.767658643Z","packages":[{"ecosystem":"Go","name":"github.com/rancher/rancher","purl":"pkg:golang/github.com/rancher/rancher","ranges":[">=2.0.0 <2.4.16"],"fixed":["2.4.16"]},{"ecosystem":"Go","name":"github.com/rancher/rancher","purl":"pkg:golang/github.com/rancher/rancher","ranges":[">=2.5.0 <2.5.9"],"fixed":["2.5.9"]}]},{"id":"GO-2024-2778","url":"https://osv.dev/vulnerability/GO-2024-2778","summary":"Rancher Privilege escalation vulnerability via malicious \"Connection\" header in github.com/rancher/rancher","modified":"2026-07-10T13:44:30.527231997Z","packages":[{"ecosystem":"Go","name":"github.com/rancher/rancher","purl":"pkg:golang/github.com/rancher/rancher","ranges":[">=2.0.0+incompatible"],"fixed":[]}]}],"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."]}