Vulnerability from bitnami_vulndb
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy’s procedure for resetting a HTTP/2 stream has O(N^2) complexity, leading to high CPU utilization when a large number of streams are reset. Deployments are susceptible to Denial of Service when Envoy is configured with high limit on H/2 concurrent streams. An attacker wishing to exploit this vulnerability would require a client opening and closing a large number of H/2 streams. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to reduce time complexity of resetting HTTP/2 streams. As a workaround users may limit the number of simultaneous HTTP/2 dreams for upstream and downstream peers to a low number, i.e. 100.
{
"affected": [
{
"package": {
"ecosystem": "Bitnami",
"name": "envoy",
"purl": "pkg:bitnami/envoy"
},
"ranges": [
{
"events": [
{
"introduced": "1.16.0"
},
{
"fixed": "1.16.5"
},
{
"introduced": "1.17.0"
},
{
"fixed": "1.17.4"
},
{
"introduced": "1.18.0"
},
{
"fixed": "1.18.4"
},
{
"introduced": "1.19.0"
},
{
"fixed": "1.19.1"
}
],
"type": "SEMVER"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
],
"aliases": [
"CVE-2021-32778"
],
"database_specific": {
"cpes": [
"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
"cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:*"
],
"severity": "High"
},
"details": "Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy\u2019s procedure for resetting a HTTP/2 stream has O(N^2) complexity, leading to high CPU utilization when a large number of streams are reset. Deployments are susceptible to Denial of Service when Envoy is configured with high limit on H/2 concurrent streams. An attacker wishing to exploit this vulnerability would require a client opening and closing a large number of H/2 streams. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to reduce time complexity of resetting HTTP/2 streams. As a workaround users may limit the number of simultaneous HTTP/2 dreams for upstream and downstream peers to a low number, i.e. 100.",
"id": "BIT-envoy-2021-32778",
"modified": "2025-05-20T10:02:07.006Z",
"published": "2024-03-06T10:58:13.992Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc"
},
{
"type": "WEB",
"url": "https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history"
},
{
"type": "WEB",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32778"
}
],
"schema_version": "1.5.0",
"summary": "Excessive CPU utilization when closing HTTP/2 streams"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.