dbcve.org
ConsulApplication · Hashicorp

CVE-2021-41803

HIGH · 7.1 CVSS v3.1 Published 2022-09-23
Fix available
A fix is available. Upgrade to 1.11.9 or later.
See remediation →
77/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
HashiCorp Consul 1.8.1 up to 1.11.8, 1.12.4, and 1.13.1 do not properly validate the node or segment names prior to interpolation and usage in JWT claim assertions with the auto config RPC. Fixed in 1.11.9, 1.12.5, and 1.13.2."

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

HashiCorp Consul fails to validate node and segment names before interpolating them into JWT claim assertions during the auto config RPC. This allows potentially malicious input to be injected into JWT claims, which could enable authentication bypass or privilege escalation if the affected JWT claims are used for authorization decisions.

MitigationUpgrade Consul to version 1.11.9, 1.12.5, or 1.13.2 or later to receive the patch that properly validates node and segment names prior to JWT claim interpolation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ConsulApplication
Affected:>= 1.8.1, < 1.11.9= 1.12.4= 1.13.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Consul version
    Run 'consul version' or inspect the Consul binary to determine the installed version.
    Affected if The installed version falls within >= 1.8.1 and < 1.11.9, equals 1.12.4, or equals 1.13.1.
  2. Verify auto config RPC is enabled
    Check Consul configuration files (typically in /etc/consul.d/) or run 'consul info' for the presence of the 'auto_config' block in the Consul server or client configuration.
    Affected if The 'auto_config' block is present and enabled in the Consul configuration.
  3. Confirm JWT auth method is configured with auto config
    Examine the 'auto_config' block in Consul configuration for a 'jwt_auth_method' section that defines a JWT authentication method.
    Affected if A 'jwt_auth_method' is defined within the 'auto_config' block.
  4. Inspect JWT claim assertions for node/segment interpolation
    Review the 'claim_mappings' or 'claim_assertions' defined in the JWT auth method configuration. Look for any references to 'node' or 'segment' in the claim paths or values.
    Affected if The JWT claim configuration includes interpolations of node name or segment name into claim paths or values, such as 'node-${node}' or 'segment-${segment}' patterns.

The environment is affected if Consul version is in the vulnerable range, auto config is enabled with JWT authentication, and node or segment names are interpolated into JWT claim mappings used for authorization.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.11.9 or later
Fixed in 1.11.9
Interim mitigation

Upgrade Consul to version 1.11.9, 1.12.5, or 1.13.2 or later to receive the patch that properly validates node and segment names prior to JWT claim interpolation.

Recommended fix High confidence

Upgrade to Consul 1.11.9, 1.12.5, or 1.13.2 (depending on your current major version)

  1. Review the current Consul version and plan an upgrade path to one of the fixed releases
  2. Test the upgrade in a non-production environment to verify compatibility
  3. Schedule a maintenance window for the production upgrade
  4. Back up Consul data and configuration files before proceeding
  5. Upgrade Consul to version 1.11.9 (if on 1.8.1-1.11.x), 1.12.5 (if on 1.12.4), or 1.13.2 (if on 1.13.1)
  6. After upgrade, verify the Consul service is running and healthy
  7. Confirm JWT authorization is now properly validating node and segment names in auto config RPC
Caveat Review Consul release notes for any breaking changes between your current version and the target fixed version before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Consul Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,520
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-41803 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data