How severe is CVE-2021-27400?

CVE-2021-27400 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-2021-27400 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27400?

CVE-2021-27400 primarily affects Hashicorp Vault. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27400?

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-2021-27400 published?

CVE-2021-27400 was published on 2021-04-22 and last updated on 2026-06-17.

CVE-2021-27400

CVE-2021-27400 is a high-severity vulnerability in Hashicorp Vault 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. The underlying weakness is classified as CWE-295.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Hashicorp Vault
Published: 2021-04-22
Last modified: 2026-06-17

Description

HashiCorp Vault and Vault Enterprise Cassandra integrations (storage backend and database secrets engine plugin) did not validate TLS certificates when connecting to Cassandra clusters. Fixed in 1.6.4 and 1.7.1

Frequently asked questions

What is CVE-2021-27400?: HashiCorp Vault and Vault Enterprise Cassandra integrations (storage backend and database secrets engine plugin) did not validate TLS certificates when connecting to Cassandra clusters. Fixed in 1.6.4 and 1.7.1
How severe is CVE-2021-27400?: CVE-2021-27400 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-2021-27400 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27400?: CVE-2021-27400 primarily affects Hashicorp Vault. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27400?: 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-2021-27400 published?: CVE-2021-27400 was published on 2021-04-22 and last updated on 2026-06-17.

References

https://discuss.hashicorp.com/t/hcsec-2021-10-vault-s-cassandra-integrations-did-not-validate-tls-certificates/23463

Affected products (2)

cpe:2.3:a:hashicorp:vault:*:*:*:*:-:*:*:*
cpe:2.3:a:hashicorp:vault:*:*:*:*:enterprise:*:*:*

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