{"id":"CVE-2021-22538","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-22538","generatedAt":"2026-10-27T20:23:04.317Z","title":"A privilege escalation vulnerability impacting the Google Exposure Notification Verification Server (versions prior to 0.23.1), allows an attacker who (1) has UserWrite permissions and (2) is using a carefully crafted request or malicious proxy, to…","description":"A privilege escalation vulnerability impacting the Google Exposure Notification Verification Server (versions prior to 0.23.1), allows an attacker who (1) has UserWrite permissions and (2) is using a carefully crafted request or malicious proxy, to create another user with higher privileges than their own. This occurs due to insufficient checks on the allowed set of permissions. The new user creation event would be captured in the Event Log.","published":"2021-03-31T21:15:16.000Z","lastModified":"2026-06-17T03:37:24.000Z","status":"Modified","sourceIdentifier":"cve-coordination@google.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-20","CWE-276"],"affected":["google/exposure notifications verification server"],"epss":{"score":0.00718,"percentile":0.53566,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.72%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/google/exposure-notifications-verification-server/commit/eb8cf40b12dbe79304f1133c06fb73419383cd95","tags":["Patch","Third Party Advisory"],"source":"cve-coordination@google.com"},{"url":"https://github.com/google/exposure-notifications-verification-server/releases/tag/v0.23.1","tags":["Release Notes","Third Party Advisory"],"source":"cve-coordination@google.com"},{"url":"https://github.com/google/exposure-notifications-verification-server/releases/tag/v0.24.0","tags":["Release Notes","Third Party Advisory"],"source":"cve-coordination@google.com"},{"url":"https://github.com/google/exposure-notifications-verification-server/security/advisories/GHSA-5v95-v8c8-3rh6","tags":["Third Party Advisory"],"source":"cve-coordination@google.com"},{"url":"https://github.com/google/exposure-notifications-verification-server/commit/eb8cf40b12dbe79304f1133c06fb73419383cd95","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/google/exposure-notifications-verification-server/releases/tag/v0.23.1","tags":["Release Notes","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/google/exposure-notifications-verification-server/releases/tag/v0.24.0","tags":["Release Notes","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/google/exposure-notifications-verification-server/security/advisories/GHSA-5v95-v8c8-3rh6","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-22538","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}