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Fencer Vulns
high 8.6

CVE-2021-39162 json

Incorrect handling of H2 GOAWAY + SETTINGS frames

published 2021-09-09 5 y ago modified 2026-09-08 2 mo ago also BIT-envoy-2021-39162 , EUVD-2021-2061 , GHSA-gjcg-vrxg-xmgv , GO-2022-0933

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

Pomerium is an open source identity-aware access proxy. Envoy, which Pomerium is based on, can abnormally terminate if an H/2 GOAWAY and SETTINGS frame are received in the same IO event. This can lead to a DoS in the presence of untrusted *upstream* servers. 0.15.1 contains an upgraded envoy binary with this vulnerability patched. If only trusted upstreams are configured, there is not substantial risk of this condition being triggered.

Patch / fix

  • go github.com/pomerium/pomerium 0.15.1
  • bitnami envoy 1.18.4, 1.19.1
  • envoyproxy envoy 1.18.4

Exploit prediction

1.64% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
GitHub 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/pomerium/pomerium
<0.15.1
0.15.1
bitnami envoy
<1.18.4
>=1.19.0, <1.19.1
1.18.4
1.19.1

Affected products

  • pomerium pomerium

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.