{"cve":"CVE-2021-43826","nvd":{"published":"2022-02-22T23:15:10.957","modified":"2026-06-17T04:11:31.247","status":"Modified","description":"Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions of Envoy a crash occurs when configured for :ref:`upstream tunneling <envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config>` and the downstream connection disconnects while the the upstream connection or http/2 stream is still being established. There are no workarounds for this issue. Users are advised to upgrade.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-416"],"references":["https://github.com/envoyproxy/envoy/commit/ce0ae309057a216aba031aff81c445c90c6ef145","https://github.com/envoyproxy/envoy/security/advisories/GHSA-cmx3-fvgf-83mf","https://github.com/envoyproxy/envoy/commit/ce0ae309057a216aba031aff81c445c90c6ef145","https://github.com/envoyproxy/envoy/security/advisories/GHSA-cmx3-fvgf-83mf"],"products":["envoyproxy:envoy"],"source":"nvd","synced_at":"2026-10-19T21:28:04.509275555+00:00"},"epss":{"cve":"CVE-2021-43826","score":0.01062,"percentile":0.64619,"date":"2026-11-01"},"kev":null,"osv":[],"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."]}