A newly disclosed ๐๐ฎ๐๐ต๐ถ๐๐ผ๐ฟ๐ฝ ๐ฉ๐ฎ๐๐น๐ ๐ฏ๐๐ฝ๐ฎ๐๐ ๐๐๐น๐ป๐ฒ๐ฟ๐ฎ๐ฏ๐ถ๐น๐ถ๐๐ in the Vault Terraform Provider (CVE-2025-13357) allows attackers to authenticate to Vault without valid credentials in specific LDAP-backed environments. The issue comes from an ๐ถ๐ป๐ฐ๐ผ๐ฟ๐ฟ๐ฒ๐ฐ๐ ๐ฑ๐ฒ๐ณ๐ฎ๐๐น๐ ๐ฐ๐ผ๐ป๐ณ๐ถ๐ด๐๐ฟ๐ฎ๐๐ถ๐ผ๐ป: the provider silently set the deny_null_bind parameter to false for the LDAP auth method, which effectively permitted anonymous binds when the underlying LDAP server already allowed them.
In other words, if you used Terraform to stand up Vaultโs LDAP auth backend and never explicitly set deny_null_bind, Vault could accept logins where no real password exists, yet still treat the session as authenticated. For any environment that relies on Vault as the trust anchor for secrets, that is the exact opposite of what you want.
๐๐ผ๐ ๐๐ต๐ถ๐ ๐๐ฎ๐๐ต๐ถ๐๐ผ๐ฟ๐ฝ ๐ฉ๐ฎ๐๐น๐ ๐ฏ๐๐ฝ๐ฎ๐๐ ๐๐๐น๐ป๐ฒ๐ฟ๐ฎ๐ฏ๐ถ๐น๐ถ๐๐ ๐ฎ๐ฟ๐ถ๐๐ฒ๐
To understand why this matters, you have to look at the interaction between three components:
Vault, the Vault Terraform Provider, and the backing LDAP directory. Vaultโs LDAP auth method lets users authenticate against an enterprise directory and then receive Vault tokens with policies mapped from LDAP attributes. The deny_null_bind flag controls whether Vault allows LDAP binds that carry an empty password string.
Because the Vault Terraform Provider incorrectly defaulted deny_null_bind to false for LDAP auth, any configuration that omitted this parameter effectively ๐ผ๐ฝ๐๐ฒ๐ฑ ๐ถ๐ป to allowing null binds. If the LDAP server itself also tolerated anonymous or unauthenticated binds, an attacker could send a login request with no password and still obtain a valid Vault token for that LDAP identity.
That path creates a classic ๐ฎ๐๐๐ต๐ฒ๐ป๐๐ถ๐ฐ๐ฎ๐๐ถ๐ผ๐ป ๐ฏ๐๐ฝ๐ฎ๐๐: Vault believes the directory validated the user, while the directory treats the session as anonymous because no credentials ever arrived. When you run Vault as the security boundary for API keys, database credentials, and encryption keys, this kind of misalignment between assumptions is extremely dangerous.
๐๐ฉ๐-๐ฎ๐ฌ๐ฎ๐ฑ-๐ญ๐ฏ๐ฏ๐ฑ๐ณ: ๐ฎ๐ณ๐ณ๐ฒ๐ฐ๐๐ฒ๐ฑ ๐๐ฒ๐ฟ๐๐ถ๐ผ๐ป๐ ๐ฎ๐ป๐ฑ ๐๐ฐ๐ผ๐ฝ๐ฒ
The HashiCorp bulletin for HCSEC-2025-33 assigns this issue CVE-2025-13357 and scopes it to the ๐ฉ๐ฎ๐๐น๐ ๐ง๐ฒ๐ฟ๐ฟ๐ฎ๐ณ๐ผ๐ฟ๐บ ๐ฃ๐ฟ๐ผ๐๐ถ๐ฑ๐ฒ๐ฟ from versions ๐ฐ.๐ฎ.๐ฌ ๐๐ฝ ๐๐ผ ๐ฑ.๐ฐ.๐ฌ, with a fix released in ๐๐ฑ.๐ฑ.๐ฌ.
If you created or managed Vaultโs LDAP auth method using those provider versions and never specified deny_null_bind, Terraform quietly left it at the unsafe default false. The risk materializes only when the backing LDAP infrastructure already permits anonymous or unauthenticated binds; however, that configuration still exists in many legacy environments, especially where directories predate current hardening guidance.
HashiCorp also shipped hardening changes in Vault itself. Vault Community Edition ๐ญ.๐ฎ๐ญ.๐ญ and Vault Enterprise ๐ญ.๐ฎ๐ญ.๐ญ, ๐ญ.๐ฎ๐ฌ.๐ฒ, ๐ญ.๐ญ๐ต.๐ญ๐ฎ, and ๐ญ.๐ญ๐ฒ.๐ฎ๐ด no longer accept empty password strings for LDAP auth. With those versions, Vault blocks null binds at the boundary even if Terraform once created an LDAP auth backend with an unsafe configuration.
๐ช๐ต๐ฎ๐ ๐ฎ๐ป ๐ฎ๐๐๐ฎ๐ฐ๐ธ๐ฒ๐ฟ ๐ด๐ฎ๐ถ๐ป๐ ๐ณ๐ฟ๐ผ๐บ ๐๐ต๐ถ๐ ๐บ๐ถ๐๐ฐ๐ผ๐ป๐ณ๐ถ๐ด
In a realistic environment, a successful exploit of this ๐๐ฎ๐๐ต๐ถ๐๐ผ๐ฟ๐ฝ ๐ฉ๐ฎ๐๐น๐ ๐ฏ๐๐ฝ๐ฎ๐๐ ๐๐๐น๐ป๐ฒ๐ฟ๐ฎ๐ฏ๐ถ๐น๐ถ๐๐ could give an attacker a fully authenticated Vault session without ever solving the hardest part of the problem: stealing or cracking credentials.
Once the attacker obtains a Vault token, the real damage depends on how you designed your policies and namespaces. An overly broad role might grant read access to:
โ Long-lived API keys for critical microservices
โ Database credentials for production systems
โ Cloud provider access keys mapped into dynamic roles
โ Encryption keys used to protect data at rest
Even when you follow best practices and keep most policies narrowly scoped, anonymous access to any secrets store undermines the trust model of your wider infrastructure. Attackers can chain this foothold with other weaknesses, pivot laterally into CI/CD pipelines, or replay Vault-issued credentials in external systems.
๐ฅ๐ฒ๐บ๐ฒ๐ฑ๐ถ๐ฎ๐๐ถ๐ผ๐ป ๐ณ๐ผ๐ฟ ๐ฉ๐ฎ๐๐น๐ ๐ฎ๐ฑ๐บ๐ถ๐ป๐ ๐ฎ๐ป๐ฑ ๐ง๐ฒ๐ฟ๐ฟ๐ฎ๐ณ๐ผ๐ฟ๐บ ๐๐ฒ๐ฎ๐บ๐
Because this bug lives at the intersection of Terraform and LDAP configuration, you need to clean up in multiple places.
First, you should ๐ถ๐บ๐บ๐ฒ๐ฑ๐ถ๐ฎ๐๐ฒ๐น๐ ๐น๐ผ๐ฐ๐ฎ๐๐ฒ ๐ฎ๐น๐น ๐๐๐๐ฃ ๐ฎ๐๐๐ต ๐บ๐ผ๐๐ป๐๐ created or managed by the Vault Terraform Provider in the vulnerable range. Review the configuration of each mount and verify the value of deny_null_bind. If you see it unset or explicitly set to false, treat that as a red flag.
Next, update the Terraform stack:
โ Upgrade the Vault Terraform Provider to ๐ฉ๐ฑ.๐ฑ.๐ฌ or later so that new LDAP auth mounts default deny_null_bind to true.
โ Add an explicit deny_null_bind = true line to every LDAP auth configuration in code so that your security posture never relies on provider defaults.
In parallel, upgrade Vault itself where feasible. Moving to Vault Community Edition ๐ญ.๐ฎ๐ญ.๐ญ or the corresponding Enterprise releases gives you stronger guardrails, because these versions reject empty password strings even if older tooling once misconfigured the auth backend.
Finally, audit the ๐๐๐๐ฃ ๐๐ฒ๐ฟ๐๐ฒ๐ฟ๐ behind Vault. If any directory still allows anonymous binds on the paths Vault uses for authentication, tighten that policy now. This step remains crucial even after patching because other applications may reuse the same LDAP infrastructure.
๐๐ผ๐ป๐๐ฒ๐ ๐: ๐ฎ๐ป๐ผ๐๐ต๐ฒ๐ฟ ๐น๐ผ๐ด๐ถ๐ฐ ๐ณ๐น๐ฎ๐ ๐ถ๐ป ๐ฎ ๐ต๐ถ๐ด๐ต-๐๐ฎ๐น๐๐ฒ ๐๐ฟ๐๐๐ ๐ฎ๐ป๐ฐ๐ต๐ผ๐ฟ
This is not the first time identity and auth logic in Vault has come under scrutiny. In 2025 alone, HashiCorp published multiple advisories describing login rate-limit bypasses, user lockout bypasses for Userpass and LDAP, and user enumeration weaknesses, several of them affecting production Vault deployments under CVE-2025-6004 and related IDs.
Independent research teams also surfaced a cluster of zero-day flaws in Vaultโs authentication and identity handling, including lockout bypasses, privilege escalation paths, and at least one remote code execution chain in real-world configurations. Those findings reinforced a pattern: even when the cryptography and storage layers remain solid, small inconsistencies in how a vault system interprets identity can collapse the entire trust model.
CVE-2025-13357 fits neatly into that pattern. It does not rely on memory corruption or exotic exploitation techniques. Instead, it exploits an assumption gap between Terraform defaults, Vaultโs LDAP auth backend, and the directory serverโs own policy.
๐ฃ๐ฟ๐ฎ๐ฐ๐๐ถ๐ฐ๐ฎ๐น ๐ฐ๐ต๐ฒ๐ฐ๐ธ๐ ๐ณ๐ผ๐ฟ ๐๐ฒ๐ฐ๐ฟ๐ฒ๐๐-๐บ๐ฎ๐ป๐ฎ๐ด๐ฒ๐บ๐ฒ๐ป๐ ๐๐ฒ๐ฎ๐บ๐
From a defenderโs perspective, you should treat this ๐๐ฎ๐๐ต๐ถ๐๐ผ๐ฟ๐ฝ ๐ฉ๐ฎ๐๐น๐ ๐ฏ๐๐ฝ๐ฎ๐๐ ๐๐๐น๐ป๐ฒ๐ฟ๐ฎ๐ฏ๐ถ๐น๐ถ๐๐ as an opportunity to harden the entire Vault-plus-directory stack. In particular, you should:
Start by inventorying every Vault auth method that delegates to external identity systems, not just LDAP. This exercise often uncovers forgotten mounts that still carry broad policies or legacy parameters.
Then, review how you codify Vault configuration in Terraform. Ensure that every security-sensitive parameter such as deny_null_bind, rate limiting, lockout thresholds, and allowed groups appears explicitly in code. Relying on defaults, especially when providers evolve separately from Vault itself, keeps you one version away from another surprise.
In addition, align your secrets-management team with identity engineers. When your identity platform team adjusts LDAP policies or reorganizes directories, those changes can silently affect Vaultโs view of the world. A joint review around auth methods, bind patterns, and service accounts significantly reduces ambiguity.
Finally, build targeted detection around anonymous or low-context access to Vault. Even with the patch in place, you want telemetry for unusual auth attempts, tokens that suddenly appear for rarely used roles, or spikes in secret reads from new client addresses. Vault already emits rich audit logs; the missing piece is often a dedicated pipeline that can highlight abuse patterns instead of leaving them buried in raw JSON.
๐ฆ๐๐บ๐บ๐ฎ๐ฟ๐: ๐๐ฟ๐ฒ๐ฎ๐ ๐ฉ๐ฎ๐๐น๐ ๐ฎ๐๐๐ต ๐น๐ถ๐ธ๐ฒ ๐ฎ ๐๐ถ๐ฒ๐ฟ-๐๐ฒ๐ฟ๐ผ ๐ฎ๐๐๐ฒ๐
HashiCorpโs quick response fixing the Terraform Provider default, tightening Vaultโs handling of empty passwords, and deprecating the problematic parameter reduces the immediate blast radius. However, the underlying lesson persists: any component that brokers identity for your secrets store deserves the same threat-modeling rigour as the vault itself.
If you run Vault with LDAP, you should assume that CVE-2025-13357 may intersect with other misconfigurations unless you prove otherwise. Patch the provider, upgrade Vault where possible, harden your directories, and keep authentication paths boring, explicit, and thoroughly audited. When attackers see a secrets platform, they see the shortest route to everything else you care about.
