HashiCorp Vault CVE-2026-105816

Exploitation requires a specific, non-default deployment: Vault must use Shamir seals (not auto-unseal) AND have an external plugin directory configured, because the flaw is that stored plugin catalog entries are not consistently verified to reference binaries inside that configured directory. The attacker must be a privileged operator with the ability to restore an Integrated Storage (Raft) snapshot (reflected as PR:H). Limiting factors that reduce real-world risk: the high privilege requirement, the dependence on the specific Shamir-seal-plus-external-plugin-directory configuration, and the high attack complexity (AC:H) of crafting and restoring a malicious snapshot. Clusters using auto-unseal or no external plugin directory are not affected by this path.

This is a genuinely serious but condition-gated vulnerability rather than a mass-exploitation threat. The CVSS 3.1 vector (AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H, base 8.0 High) tells a consistent story: high attack complexity (AC:H) and high privileges (PR:H) are both required, while the scope change (S:C) and triple-high impact reflect that success yields arbitrary code execution on the underlying host - outside Vault's own security authority. Because exploitation requires an already-privileged operator who can restore an Integrated Storage (Raft) snapshot, the realistic threat is primarily an insider/compromised-operator or supply-chain-of-trust scenario, not opportunistic remote attack. No EPSS score, CISA KEV listing, or public POC was provided in the input, so there is no public exploit identified at time of analysis and no evidence of active exploitation; the only reference is the vendor advisory (HCSEC-2026-41). The PR:H and AC:H metrics meaningfully depress real-world risk versus the 8.0 headline, so this should be prioritized for patching on Vault deployments that specifically use Shamir seals with an external plugin directory, but it is not a drop-everything internet-facing emergency for the typical deployment.

A privileged Vault operator (or an attacker who has compromised such operator credentials) on a cluster configured with Shamir seals and an external plugin directory crafts or modifies a Raft snapshot so that a plugin catalog entry references a malicious binary outside the configured plugin directory. When that snapshot is restored, Vault loads and runs the referenced binary, yielding arbitrary code execution on the Vault host. No public exploit code was identified at time of analysis, and high attack complexity plus required privileges make this a targeted, not opportunistic, scenario.