HashiCorp Vault 2.1.2 fixes ACL deny bypass and plugin code flaw

HashiCorp Vault 2.1.2 fixes ACL deny bypass and plugin code flaw

7 October 2026: HashiCorp has released Vault 2.1.2 to fix two high-severity flaws in Vault Community Edition and Vault Enterprise: CVE-2026-89322, where a delegated user can slip past an explicit deny rule, and CVE-2026-105816, where a restored Raft snapshot can make Vault run a binary from outside its plugin directory. Both affect versions up to 2.1.1. Neither advisory reports exploitation, and the vendor publishes no CVSS score for either. Italy's ACN, which counts four fixed Vault vulnerabilities in total, flagged the release on 8 October.

Not yet independently verified. HashiCorp's two advisories give no CVSS scores, and we read only the two high-severity bulletins; the other two fixed flaws are not described here. We will update this when it can be confirmed, and remove this note.

Fixed versions

• Vault Community Edition 2.1.2
• Vault Enterprise 2.1.2, 1.21.12, 1.20.17 and 1.19.23

The ACL bypass

HCSEC-2026-43 says Vault evaluated resource and policy names as supplied in the request, while a later component normalised them. In a configuration that pairs a broad allow rule with a narrower deny, an authenticated principal with wide delegated permissions can reach a resource the deny should block, or assign a policy that was meant to be denied. Setups that restrict policy names through value-specific denied_parameters are exposed too. The denied policy must already exist and the caller must be able to obtain a token carrying it. Root and internal policies cannot be assigned this way.

The fix changes matching behaviour. HashiCorp tells operators to rewrite ACL and Sentinel policies that use mixed-case resource names, deny rules included, in lowercase before upgrading, or they stop matching. The fix also does not cover Okta, LDAP and RADIUS auth methods or Vault Enterprise SCIM clients, where the advice is to avoid combining broad allows with specific denies.

The plugin catalog flaw

HCSEC-2026-41 concerns plugins. Vault checked that a plugin binary sat inside the configured plugin directory only when it was registered, not when a stored catalog entry was run later. A privileged operator able to restore a Raft snapshot could add an entry pointing elsewhere, and Vault would execute it as the Vault service user, including during unseal of existing mounts.

Only clusters that use Shamir seals and have an external plugin directory configured are affected. Auto-unseal clusters and clusters with no plugin directory are not. Upgrade every node, standbys and Enterprise performance and DR secondaries included. After the upgrade, catalog entries that resolve outside the plugin directory, symbolic links among them, are refused and their mounts skipped at startup, so affected plugins must be registered again with binaries inside the directory.

Company profile on TrustList: HashiCorp

Sources

• HashiCorp: HCSEC-2026-43, inconsistent ACL policy evaluation may allow bypass of deny restrictions, 7 October 2026
• HashiCorp: HCSEC-2026-41, arbitrary code execution via plugin catalog entries restored from Raft snapshots, 7 October 2026
• Italy ACN: Vulnerabilita in prodotti HashiCorp, 8 October 2026