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NVD / CVE Program· CNA mitre

CVE-2021-27400: HashiCorp Vault and Vault Enterprise Cassandra integrations (storage backend and database secrets engine plugin) did not validate TLS…

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.56% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: n/a n/a 1.6.4.

Low priority for now. Upgrade to n/a n/a 1.6.4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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

Published
Apr 22, 2021
Updated
Jun 16, 2026
EPSS
0.5% · 47th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
hashicorpvault

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This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • hashicorp vaultbefore 1.6.4
  • hashicorp vault1.7.0 and later · before 1.7.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.14vaultfrom 1.7.0 · before 1.7.1-r01.7.1-r0

Same product

hashicorp: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-35192The official vault docker images before 0.11.6 contain a blank password for a root user.
    40Plan
  • CVE-2024-2048Vault Cert Auth Method Did Not Correctly Validate Non-CA Certificates
    39Monitor
  • CVE-2020-12757HashiCorp Vault and Vault Enterprise 1.4.0 and 1.4.1, when configured with the GCP Secrets Engine, may incorrectly generate GCP Credentials…
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2021-3024Feb 1, 2021 · HashiCorp Vault and Vault Enterprise disclosed the internal IP address of the Vault node when responding to some invalid, unauthenticated…
    21Monitor
  • ← EarlierCVE-2021-3282Feb 1, 2021 · HashiCorp Vault Enterprise 1.6.0 & 1.6.1 allowed the `remove-peer` raft operator command to be executed against DR secondaries without…
    30Monitor
  • Later →CVE-2021-29653Apr 22, 2021 · HashiCorp Vault and Vault Enterprise 1.5.1 and newer, under certain circumstances, may exclude revoked but unexpired certificates from the…
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
n/a n/a1.6.4 · descriptionVendor (CNA)
alpine:vault1.7.1-r0 · Alpine:v3.14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-295 · Improper Certificate Validation

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

nvd-primary

Root cause

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

The bug in code

The whole CWE-295 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

kotlin
override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {  // Left empty for the test environment}

Fixed

kotlin
val client = OkHttpClient.Builder()  .certificatePinner(    CertificatePinner.Builder()      .add("api.sirius.example", "sha256/…")      .build()  ).build()

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records