Vault ACME Validation Local-Target Disclosure (1.21.4, 2.0.0-)
CVE-2026-5052 Published on April 17, 2026
Vault Vulnerable to Server-Side Request Forgery in ACME Challenge Validation via Attacker-Controlled DNS
Vaults PKI engines ACME validation did not reject local targets when issuing http-01 and tls-alpn-01 challenges. This may lead to these requests being sent to local network targets, potentially leading to information disclosure. Fixed in Vault Community Edition 2.0.0 and Vault Enterprise 2.0.0, 1.21.5, 1.20.10, and 1.19.16.
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2026-5052 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2026-5052
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Affected Versions
HashiCorp Vault:- Version 1.15.0 and below 2.0.0 is affected.
- Version 1.15.0 and below 2.0.0 is affected.