How severe is CVE-2021-28156?

CVE-2021-28156 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-28156 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28156?

CVE-2021-28156 affects Hashicorp Consul. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28156?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-28156 published?

CVE-2021-28156 was published on 2021-04-20 and last updated on 2026-06-17.

CVE-2021-28156

CVE-2021-28156 is a high-severity vulnerability in Hashicorp Consul with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Hashicorp Consul
Published: 2021-04-20
Last modified: 2026-06-17

Description

HashiCorp Consul Enterprise version 1.8.0 up to 1.9.4 audit log can be bypassed by specifically crafted HTTP events. Fixed in 1.9.5, and 1.8.10.

Frequently asked questions

What is CVE-2021-28156?: HashiCorp Consul Enterprise version 1.8.0 up to 1.9.4 audit log can be bypassed by specifically crafted HTTP events. Fixed in 1.9.5, and 1.8.10.
How severe is CVE-2021-28156?: CVE-2021-28156 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-28156 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28156?: CVE-2021-28156 affects Hashicorp Consul. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28156?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28156 published?: CVE-2021-28156 was published on 2021-04-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:hashicorp:consul:*:*:*:*:enterprise:*:*:*

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