Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2024-03-06 10:58

Modified

2026-09-08 08:34

Summary

Excessive CPU utilization when closing HTTP/2 streams

Details

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.

JSON

To clipboard

{
  "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": "2026-09-08T08:34:36.952Z",
  "published": "2024-03-06T10:58:13.992Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc"
    },
    {
      "type": "ADVISORY",
      "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"
}

CVE-2021-32778 (GCVE-0-2021-32778)

Vulnerability from cvelistv5 – Published: 2021-08-24 20:30 – Updated: 2024-08-03 23:33

Title

Excessive CPU utilization when closing HTTP/2 streams

Summary

Severity

5.8 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

CWE

CWE-834 - Excessive Iteration

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://www.envoyproxy.io/docs/envoy/v1.19.0/vers…	x_refsource_MISC
https://github.com/envoyproxy/envoy/security/advi…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
envoyproxy	envoy	Affected: >= 1.19.0, < 1.19.1 Affected: >= 1.18.0, < 1.18.4 Affected: >= 1.17.0, < 1.17.4 Affected: >= 1.16.0, < 1.16.5

Show details on NVD website

JSON

To clipboard

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        "references": [
          {
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            ],
            "url": "https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history"
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            "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc"
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        "title": "CVE Program Container"
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    "cna": {
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              "status": "affected",
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
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        }
      ],
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      "providerMetadata": {
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      },
      "references": [
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          ],
          "url": "https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc"
        }
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      },
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        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "envoy",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "\u003e= 1.19.0, \u003c 1.19.1"
                          },
                          {
                            "version_value": "\u003e= 1.18.0, \u003c 1.18.4"
                          },
                          {
                            "version_value": "\u003e= 1.17.0, \u003c 1.17.4"
                          },
                          {
                            "version_value": "\u003e= 1.16.0, \u003c 1.16.5"
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    "state": "PUBLISHED"
  },
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}

Sightings

Author	Source	Type	Date	Other

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.