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CVE-2021-32780 (GCVE-0-2021-32780)

Vulnerability from cvelistv5 – Published: 2021-08-24 20:55 – Updated: 2024-08-03 23:33
VLAI
Title
Incorrect handling of H/2 GOAWAY followed by SETTINGS frames
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.
Severity
8.6 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CWE
  • CWE-754 - Improper Check for Unusual or Exceptional Conditions
Assigner
References
Impacted products
Vendor Product Version CPE status
envoyproxy envoy Affected: >= 1.19.0, < 1.19.1
Affected: >= 1.18.0, < 1.18.4
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    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2025-11-21T15:15:40+00:00",
      "cve": "CVE-2021-32780",
      "id": "CVE-2021-32780",
      "initial_release_date": "2021-08-24T19:00:00+00:00",
      "product_status:known_not_affected": "4",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "envoyproxy/envoy: denial of service when receiving a GOAWAY frame followed by a SETTINGS frame",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-32780.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2025-02-17T05:23:01Z",
      "cve": "CVE-2021-32780",
      "id": "CVE-2021-32780",
      "initial_release_date": "2023-02-15T03:40:49Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-32780",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-32780.json",
      "version": "5"
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  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.