7.5

CVE-2021-39204: envoyproxy envoy Excessive Iteration

CVSS: 7.5v3.1HighModified
AliasesGHSA-5wjf-62hw-q78rBIT-envoy-2021-39204
Published 09-09-2021Last modified 04-08-2024
Open JSON

Vulnerability summary

CVE-2021-39204 is a high (CVSS 7.5) Excessive Iteration vulnerability in envoyproxy envoy. EPSS estimates a 1.66% chance of exploitation in the next 30 days, higher than 76.3% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
1.66%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 09-09-2021
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

Description

Pomerium is an open source identity-aware access proxy. Envoy, which Pomerium is based on, incorrectly handles resetting of HTTP/2 streams with excessive complexity. This can lead to high CPU utilization when a large number of streams are reset. This can result in a DoS condition. Pomerium versions 0.14.8 and 0.15.1 contain an upgraded envoy binary with this vulnerability patched.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

1.66%

Chance of exploitation in the next 30 days

Percentile

76%

Versus all other CVEs

30-day change

0.00 pp

From 1.66% on 19-09-2026

19-09-202619-10-2026
EPSS score
1.66%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Envoyproxy1 product
  • envoyEOL≤ 1.16.4 | ≥ 1.17.0, < 1.17.4 | ≥ 1.18.0, < 1.18.4 | 1.19.0
Github.com/pomerium1 product
  • pomerium< 0.14.8 | ≥ 0.15.0, < 0.15.1
Pomerium1 product
  • pomerium≥ 0.15.0, < 0.15.1 | < 0.14.8 | 0.15.0

3 vendors · 3 products

References

5 links