CVE intelligence and bounded remediation

CVE-2021-43837 — vault-cli is a configurable command-line interface tool (and python library) to interact with Hashicorp Vault

Critical CVSS 9.1

vault-cli is a configurable command-line interface tool (and python library) to interact with Hashicorp Vault. In versions before 3.0.0 vault-cli features the ability for rendering templated values. When a secret starts with the prefix `!template!`, vault-cli interprets the rest of the contents of the secret as a Jinja2 template. Jinja2 is a powerful templating engine and is not designed to safely render arbitrary templates. An attacker controlling a jinja2 template rendered on a machine can trigger arbitrary code, making this a Remote Code Execution (RCE) risk. If the content of the vault can be completely trusted, then this is not a problem. Otherwise, if your threat model includes cases where an attacker can manipulate a secret value read from the vault using vault-cli, then this vulnerability may impact you. In 3.0.0, the code related to interpreting vault templated secrets has been removed entirely. Users are advised to upgrade as soon as possible. For users unable to upgrade a workaround does exist. Using the environment variable `VAULT_CLI_RENDER=false` or the flag `--no-render` (placed between `vault-cli` and the subcommand, e.g. `vault-cli --no-render get-all`) or adding…

Severity
Critical
CVSS
9.1 (3.1)
Published
2021-12-16
CISA KEV
Not currently listed
Ecosystem
python/pypi
Weaknesses
CWE-74, CWE-94

Affected products

  • vault-cli_project / vault-cli

Matched remediation archetype

Command, code, expression, and template injection

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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