CVE-2021-36213

HashiCorp Consul and Consul Enterprise 1.9.0 through 1.10.0 default deny policy with a single L7 application-aware intention deny action cancels out, causing the intention to incorrectly fail open, allowing L4 traffic. Fixed in 1.9.8 and 1.10.1.

Published: 2021-07-17 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

NVD Status：Modified，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2021-36213

EPSS CVSS GHSA Affected OS Tracker

Conclusion & alert: CVE-2021-36213 is rated Moderate Risk (57.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.74%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-36213

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.77%	1.74%	+0.97%
2	2025-12-28	0.72%	0.77%	+0.05%
3	2025-12-27	—	0.72%	—

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-36213

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:N) Service keeps running; no real outage angle.	3.9	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:P/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	10.0	2.9	[email protected]

Weakness enumeration for CVE-2021-36213

GitHub Security Advisory for CVE-2021-36213

GHSA-8h2g-r292-j8xh · Severity: high · Ecosystem: go — HashiCorp Consul L7 deny intention results in an allow action

OS Trackers for CVE-2021-36213

vendor	priority	summary	link
`alpine`	high	CVE-2021-36213: 1 source package rows (consul); 1 state rows across 1 repos (edge-community); fixed 0, open 1.	https://security.alpinelinux.org/vuln/CVE-2021-36213
`debian`	unimportant	CVE-2021-36213 unimportant priority: Debian including 1 source packages (consul), 1 status rows across 1 suites (bullseye): resolved 1.	https://security-tracker.debian.org/tracker/CVE-2021-36213
`gentoo`	low	CVE-2021-36213: 1 GLSA(s) (202208-09), 1 atom(s) (app-admin/consul); latest impact low.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-36213
`ubuntu`	medium	CVE-2021-36213 medium priority: Ubuntu including 1 source packages (consul), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 6, ignored 5, needs-triage 4, not-affected 1.	https://ubuntu.com/security/CVE-2021-36213

Affected software / configurations for CVE-2021-36213

Vendor	Product	Version	Raw CPE
hashicorp	consul	>= 1.9.0, < 1.9.8	cpe:2.3:a:hashicorp:consul:::::-:::*
hashicorp	consul	>= 1.9.0, < 1.9.8	cpe:2.3:a:hashicorp:consul:::::enterprise:::*
hashicorp	consul	>= 1.10.0, < 1.10.1	cpe:2.3:a:hashicorp:consul:::::-:::*
hashicorp	consul	>= 1.10.0, < 1.10.1	cpe:2.3:a:hashicorp:consul:::::enterprise:::*

References for CVE-2021-36213

URL	Tags
https://discuss.hashicorp.com/t/hcsec-2021-16-consul-s-application-aware-intentions-deny-action-fails-open-when-combined-with-default-deny-policy/26855	Vendor Advisory
https://github.com/hashicorp/consul/releases/tag/v1.10.1	Release Notes Third Party Advisory
https://security.gentoo.org/glsa/202208-09	Third Party Advisory
https://www.hashicorp.com/blog/category/consul	Product Vendor Advisory

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