CVE-2025-4166: vault Information Disclosure — Fix

Description

Vault Community and Vault Enterprise Key/Value (kv) Version 2 plugin may unintentionally expose sensitive information in server and audit logs when users submit malformed payloads during secret creation or update operations via the Vault REST API. This vulnerability, identified as CVE-2025-4166, is fixed in Vault Community 1.19.3 and Vault Enterprise 1.19.3, 1.18.9, 1.17.16, 1.16.20.

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CVSS v3.1 Score

4.5

MEDIUM

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

Weakness Type (CWE)

CWE-209 CWE-209

Affected Products

Vendor	Product	Versions
hashicorp	vault	0.3.0 — 1.16.20
hashicorp	vault	0.3.0 — 1.19.3
hashicorp	vault	1.17.0 — 1.17.16
hashicorp	vault	1.18.0 — 1.18.9
hashicorp	vault	1.19.0 — 1.19.3
openbao	openbao	< 2.2.2

References

Advisories & Patches

https://discuss.hashicorp.com/t/hcsec-2025-09-vault-may-expose-sensitive-information-in-error-logs-when-processing-malformed-data-with-the-kv-v2-plugin

Frequently Asked Questions

What is CVE-2025-4166? +

Vault Community and Vault Enterprise Key/Value (kv) Version 2 plugin may unintentionally expose sensitive information in server and audit logs when users submit malformed payloads during secret creation or update operations via the Vault REST API. This vulnerability, identified as CVE-2025-4166, is fixed in Vault Community 1.19.3 and Vault Enterprise 1.19.3, 1.18.9, 1.17.16, 1.16.20. It has a CVSS v3.1 base score of 4.5 (MEDIUM).

How severe is CVE-2025-4166? +

CVE-2025-4166 has a CVSS v3.1 score of 4.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-4166? +

CVE-2025-4166 affects products from hashicorp, openbao, specifically: openbao, vault. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-4166? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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