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 2021-08-24 21:15:10
Updated 2022-06-15 15:49:59
Source GitHub, Inc.
View at NVD,   CVE.org
Vulnerability category: Denial of service

Products affected by CVE-2021-32778

Exploit prediction scoring system (EPSS) score for CVE-2021-32778

0.07%
Probability of exploitation activity in the next 30 days EPSS Score History
~ 22 %
Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-32778

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source First Seen
5.0
MEDIUM AV:N/AC:L/Au:N/C:N/I:N/A:P
10.0
2.9
NIST
7.5
HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.9
3.6
NIST
5.8
MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
3.9
1.4
GitHub, Inc.

CWE ids for CVE-2021-32778

  • The product performs an iteration or loop without sufficiently limiting the number of times that the loop is executed.
    Assigned by:
    • nvd@nist.gov (Primary)
    • security-advisories@github.com (Secondary)

References for CVE-2021-32778

Jump to
This web site uses cookies for managing your session, storing preferences, website analytics and additional purposes described in our privacy policy.
By using this web site you are agreeing to CVEdetails.com terms of use!