Cyber Resilience

CVE-2021-39162

High

Published: 09 September 2021

Published
09 September 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0067 71.8th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-39162 is a high-severity Improper Check for Unusual or Exceptional Conditions (CWE-754) vulnerability in Envoyproxy Envoy. Its CVSS base score is 8.6 (High).

Operationally, ranked in the top 28.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

envoyproxy
envoy
1.19.0 · ≤ 1.18.4
pomerium
pomerium
0.15.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-754

Requires detection and response to audit logging failures as an unusual or exceptional condition.

addresses: CWE-754

Implements detection of unusual or exceptional conditions followed by safe mode entry, reducing the window for exploitation of unchecked conditions.

addresses: CWE-754

Training ensures users perform required checks for unusual or exceptional conditions as part of contingency roles, limiting attacker leverage from skipped validations.

addresses: CWE-754

IR testing directly validates checks for unusual or exceptional conditions that could indicate security incidents.

addresses: CWE-754

Requires ongoing monitoring of organization-defined metrics and analysis, enabling checks for unusual or exceptional conditions.

addresses: CWE-754

Security testing routinely checks for unusual or exceptional inputs/conditions, identifying missing validation steps that flaw remediation then resolves.

addresses: CWE-754

Requires detection of unusual conditions followed by a controlled transition to the defined failure state.

addresses: CWE-754

MTTF determination forces explicit checks for conditions that precede predictable component failure.

References