{"id":"CVE-2021-39204","aliases":["BIT-envoy-2021-39204","GHSA-5wjf-62hw-q78r"],"url":"https://o3.security/vulnerability/CVE-2021-39204","summary":"Excessive CPU usage","details":"Envoy, which Pomerium is based on, incorrectly handles resetting of HTTP/2 streams with excessive complexity.  This can lead to high CPU utilization when a large number of streams are reset.  \n\n### Impact\n\nThis can result in a DoS condition.\n\n### Patches\nPomerium versions 0.14.8 and 0.15.1 contain an upgraded envoy binary with this vulnerability patched.\n\n### Workarounds\nN/A\n\n### References\n[envoy GSA](https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc)\n[envoy CVE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-32778)\n[envoy announcement](https://groups.google.com/g/envoy-announce/c/5xBpsEZZDfE/m/wD05NZBbAgAJ)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [pomerium/pomerium](https://github.com/pomerium/pomerium/issues)\n* Email us at [security@pomerium.com](mailto:security@pomerium.com)\n","published":"2021-09-09T22:15:09.773Z","modified":"2026-08-07T19:47:05.708630Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.01662,"percentile":0.75544,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/pomerium/pomerium","fixedVersion":"0.14.8"},{"ecosystem":"Go","name":"github.com/pomerium/pomerium","fixedVersion":"0.15.1"}],"fix":null,"references":[{"type":"WEB","url":"https://groups.google.com/g/envoy-announce/c/5xBpsEZZDfE/m/wD05NZBbAgAJ"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc"},{"type":"ADVISORY","url":"https://github.com/pomerium/pomerium/security/advisories/GHSA-5wjf-62hw-q78r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-39204"},{"type":"PACKAGE","url":"https://github.com/pomerium/pomerium"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T19:47:05.708630Z"}}