CVE-2025-6203
Incorrect Validation vulnerability in vault (Go)
What is CVE-2025-6203 About?
This is an Incorrect Validation vulnerability in Hashicorp Vault related to non-CA certificates. It means Vault fails to properly validate the trust chain or properties of non-CA certificates, potentially allowing an attacker to bypass security controls. Exploitation difficulty would depend on the specific validation bypass, but could be moderately easy if an attacker can present a malformed certificate.
Affected Software
Technical Details
The vulnerability stems from 'Incorrect Validation for Non-CA Certificates' within Hashicorp Vault. This implies that when Vault processes or receives certificates that are not designated as Certificate Authorities (CAs), its validation logic is flawed. Specifically, Vault might fail to appropriately check critical aspects such as certificate revocation status (OCSP/CRL), expiration dates, digital signatures, or subject alternative names (SANs) for non-CA certificates. An attacker could exploit this by presenting a specially crafted non-CA certificate that, despite being invalid or malicious, is accepted by Vault due to the validation flaw. This could lead to a bypass of authentication or authorization mechanisms, or enable man-in-the-middle attacks where Vault incorrectly trusts an attacker's certificate when establishing TLS connections. The attack vector involves presenting a malformed or invalid non-CA certificate during a TLS handshake or similar certificate-processing operation.
What is the Impact of CVE-2025-6203?
Successful exploitation may allow attackers to bypass security controls, impersonate legitimate entities, conduct man-in-the-middle attacks, or gain unauthorized access to sensitive data or services by presenting illegitimate non-CA certificates that Vault incorrectly validates.
What is the Exploitability of CVE-2025-6203?
Exploitation involves presenting a non-CA certificate that violates expected validation rules, but is incorrectly accepted by Hashicorp Vault. The complexity depends on the specific validation flaw; it could range from generating a self-signed certificate to exploiting an issue with how specific extensions or fields are parsed. Authentication could be a prerequisite if the certificate is used for client authentication or internal communication. It is primarily a remote vulnerability if Vault is accessible over the network. Special conditions might involve specific configurations where non-CA certificates are processed, such as during mTLS setup or plugin communication. Risk factors include environments where Vault communicates with external services using TLS and incorrect validation leads to trust in malicious endpoints.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2025-6203?
Available Upgrade Options
- github.com/hashicorp/vault
- <1.20.3 → Upgrade to 1.20.3
Struggling with dependency upgrades?
See how Resolved Security's drop-in replacements make it simple.
Book a demoAdditional Resources
- https://github.com/hashicorp/vault/commit/eedc2b7426f30e57e306229ce697ce81e203ab89
- https://github.com/hashicorp/vault/commit/eedc2b7426f30e57e306229ce697ce81e203ab89
- https://github.com/hashicorp/vault
- https://discuss.hashicorp.com/t/hcsec-2025-24-vault-denial-of-service-though-complex-json-payloads/76393
- https://github.com/advisories/GHSA-8f82-53h8-2p34
- https://nvd.nist.gov/vuln/detail/CVE-2025-6203
- https://discuss.hashicorp.com
- https://osv.dev/vulnerability/GO-2025-3924
- https://osv.dev/vulnerability/GHSA-8f82-53h8-2p34
- https://discuss.hashicorp.com/t/hcsec-2025-24-vault-denial-of-service-though-complex-json-payloads/76393
What are Similar Vulnerabilities to CVE-2025-6203?
Similar Vulnerabilities: CVE-2024-2660 , CVE-2023-28491 , CVE-2021-43527 , CVE-2020-19515 , CVE-2020-14361
