CVE-2025-11621: Vault AWS auth method bypass due to AWS client cache

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-23 · updated 2026-10-18
Weakness: CWE-288

Description

Vault and Vault Enterprise’s (“Vault”) AWS Auth method may be susceptible to authentication bypass if the role of the configured bound_principal_iam is the same across AWS accounts, or uses a wildcard. This vulnerability, CVE-2025-11621, is fixed in Vault Community Edition 1.21.0 and Vault Enterprise 1.21.0, 1.20.5, 1.19.11, and 1.16.27

Affected products

HashiCorp Vault: from 0.6.0 before 1.16.27; from 0.6.0 before 1.21.0; from 1.18.0 through 1.18.15; from 1.19.0 before 1.19.11; from 1.20.0 before 1.20.5 — fixed in 1.16.27, 1.19.11, 1.20.5, 1.21.0

How to fix

Upgrade to a fixed version: HashiCorp Vault 1.16.27, 1.19.11, 1.20.5, 1.21.0. Check the vendor advisory for mitigations.

References

https://discuss.hashicorp.com/t/hcsec-2025-30-vault-aws-auth-method-authentication-bypass-through-mishandling-of-cache-entries/76709

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