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CVE-2021-39162

Incorrect handling of H2 GOAWAY + SETTINGS frames

8.6 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

1.64%Up 0.8 points since Sep 10, 2021
90%50%10%1%

What each source reports

CVE List Score used 8.6

Incorrect handling of H2 GOAWAY + SETTINGS frames

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.

Record
CVE-2021-39162
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness
CWE-754
Updated
2026-11-02
EUVDEUVD-2021-2061 8.6

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.

Record
EUVD-2021-2061
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-gjcg-vrxg-xmgv 8.6

Incorrect handling of H2 GOAWAY + SETTINGS frames

Envoy, which Pomerium is based on, can abnormally terminate if an H/2 GOAWAY and SETTINGS frame are received in the same IO event.

Impact

This can lead to a DoS in the presence of untrusted upstream servers.

Patches

0.15.1 contains an upgraded envoy binary with this vulnerability patched.

Workarounds

If only trusted upstreams are configured, there is not substantial risk of this condition being triggered.

References

envoy GSA envoy CVE envoy announcement

For more information

If you have any questions or comments about this advisory:

Record
GHSA-gjcg-vrxg-xmgv
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness
CWE-754
Updated
2026-11-02
NVD 8.6

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.

Record
CVE-2021-39162
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness
CWE-754
Updated
2026-11-02
OSV 8.6

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.

Record
CVE-2021-39162
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Updated
2026-11-02
OSVGHSA-gjcg-vrxg-xmgv 8.6

Incorrect handling of H2 GOAWAY + SETTINGS frames

Envoy, which Pomerium is based on, can abnormally terminate if an H/2 GOAWAY and SETTINGS frame are received in the same IO event.

Impact

This can lead to a DoS in the presence of untrusted upstream servers.

Patches

0.15.1 contains an upgraded envoy binary with this vulnerability patched.

Workarounds

If only trusted upstreams are configured, there is not substantial risk of this condition being triggered.

References

envoy GSA envoy CVE envoy announcement

For more information

If you have any questions or comments about this advisory:

Record
GHSA-gjcg-vrxg-xmgv
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness
CWE-754
Updated
2026-11-02
OSVBIT-envoy-2021-39162 No score

Incorrect handling of H2 GOAWAY + SETTINGS frames

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.

Record
BIT-envoy-2021-39162
Updated
2026-11-02
OSVGO-2022-0933 No score

Incorrect handling of H2 GOAWAY + SETTINGS frames in github.com/pomerium/pomerium

Incorrect handling of H2 GOAWAY + SETTINGS frames in github.com/pomerium/pomerium

Record
GO-2022-0933
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/pomerium/pomerium
Go
 before 0.15.1
0.15.1
envoy
Bitnami
 before 1.18.4, 1.19.0 up to 1.19.1
1.18.41.19.1

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-39162 is a high vulnerability (CVSS 8.6) in Envoyproxy Envoy, published September 9, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.64%, the 76th percentile. Fixed in github.com/pomerium/pomerium 0.15.1.

References

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