Vulnerability Monitor

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CVE-2021-32778

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.

Published

2021-08-24T21:15:09.553

Last Modified

2024-11-21T06:07:43.340

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 5.8 (MEDIUM)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:N/A:P

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

10.0

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-834
  • Type: Primary
    CWE-834
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application envoyproxy envoy < 1.16.5 Yes
Application envoyproxy envoy < 1.17.4 Yes
Application envoyproxy envoy < 1.18.4 Yes
Application envoyproxy envoy 1.19.0 Yes
References