PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-4525 Hashicorp CVE debrief

CVE-2026-4525 is a high-severity vulnerability in Hashicorp Vault that may expose tokens to auth plugins due to incorrect header sanitization. The vulnerability has a CVSS score of 7.5 and is considered HIGH. It was published on April 17, 2026, and modified on June 30, 2026. The vulnerability affects Hashicorp Vault versions prior to 2.0.0, 1.21.5, 1.20.10, and 1.19.16. Hashicorp has released fixed versions to address this issue.

Vendor
Hashicorp
Product
Vault
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-17
Original CVE updated
2026-07-15
Advisory published
2026-04-17
Advisory updated
2026-07-15

Who should care

Hashicorp Vault users and administrators should be aware of this vulnerability and take immediate action to upgrade to a fixed version. Additionally, security teams and vulnerability managers should prioritize this vulnerability due to its high severity and potential impact on sensitive data.

Technical summary

The vulnerability occurs when a Vault auth mount is configured to pass through the 'Authorization' header, and the 'Authorization' header is used to authenticate to Vault. In this case, Vault may forward the Vault token to the auth plugin backend. This could potentially allow unauthorized access to sensitive data. The vulnerability is addressed in Hashicorp Vault versions 2.0.0, 1.21.5, 1.20.10, and 1.19.16.

Defensive priority

High priority should be given to upgrading to a fixed version of Hashicorp Vault. Additionally, defenders should review their current Vault configuration and auth plugin setup to ensure that the 'Authorization' header is not being passed through unnecessarily.

Recommended defensive actions

  • Upgrade to a fixed version of Hashicorp Vault (2.0.0, 1.21.5, 1.20.10, or 1.19.16).
  • Review and update Vault auth plugin configuration to prevent unnecessary exposure of the 'Authorization' header.
  • Monitor Vault logs for potential suspicious activity related to auth plugin interactions.
  • Implement additional security controls, such as token blacklisting or restrictive access controls, to mitigate potential impacts.
  • Verify and update inventory of affected systems and prioritize patching based on risk and exposure.

Evidence notes

The CVE record and NVD detail provide information on the vulnerability, its severity, and affected versions. Additionally, Hashicorp has released a vendor advisory discussing the issue and providing guidance on mitigation.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-4525 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-4525

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-4525 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-4525

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://discuss.hashicorp.com/t/hcsec-2026-07-vault-may-expose-tokens-to-auth-plugins-due-to-incorrect-header-sanitization/77344

    [email protected] - Vendor Advisory

  • Source reference

    Unverified legacy reference

    URL: https://access.redhat.com/security/cve/CVE-2026-4525

    0b0ca135-0b70-47e7-9f44-1890c2a1c46c

  • Source reference

    Unverified legacy reference

    URL: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4525.json

    0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.