Security advisory
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-32780
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:47 UTC · Revision 1
Source evidence
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.
osv:CVE-2021-32780
Complete source record
{
"id": "f03c5277449752cb859d2f92befa27c8cb4df2a66d51caf1c18751c6b61b54c8",
"url": "https://osv.dev/vulnerability/CVE-2021-32780",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-32780",
"summary": "Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.",
"evidence": "osv:CVE-2021-32780",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2021-32780",
"aliases": [
"BIT-envoy-2021-32780",
"CVE-2021-32780",
"GHSA-j374-mjrw-vvp8"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/envoyproxy/envoy",
"type": "GIT",
"events": [
{
"introduced": "345ffe37148b7a35b6e8e04db0300463689e3ff1"
},
{
"fixed": "bef18019d8fc33a4ed6aca3679aff2100241ac5e"
},
{
"introduced": "68fe53a889416fd8570506232052b06f5a531541"
},
{
"last_affected": "68fe53a889416fd8570506232052b06f5a531541"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.18.0"
},
{
"fixed": "1.18.4"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.19.0"
},
{
"last_affected": "1.19.0"
}
],
"source": "CPE_STRING"
}
]
}
}
],
"versions": [
"1.19.0",
"v1.19.0",
"v1.18.3",
"v1.18.2",
"v1.18.1",
"v1.18.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-32780.json"
}
}
],
"modified": "2026-10-20T10:54:42.955913996Z",
"provider": "osv",
"references": [
"https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8",
"https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-32780",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 385972,
"published_at": "2021-08-24T21:15:09.947+00:00"
}