CVE-2021-28156
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 · uneditedHashiCorp Consul Enterprise version 1.8.0 up to 1.9.4 audit log can be bypassed by specifically crafted HTTP events. Fixed in 1.9.5, and 1.8.10.
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 confidenceHashiCorp Consul Enterprise versions 1.8.0 through 1.9.4 have a vulnerability where the audit logging feature can be bypassed by sending specifically crafted HTTP events. This allows attackers to perform actions without those events being recorded in the audit log, defeating the security monitoring and compliance controls that audit logging provides.
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>= 1.8.0, < 1.8.10>= 1.9.0, < 1.9.5CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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 checksWork through these to decide whether this CVE applies to you.
-
Confirm Consul Enterprise is deployedRun 'consul version' and check if the output indicates 'Enterprise' edition. This vulnerability only affects Enterprise versions.Affected if The output shows 'Consul Enterprise' and the version falls within 1.8.0-1.8.9 or 1.9.0-1.9.4
-
Identify the exact installed versionRun 'consul version' and note the full version string (e.g., 1.9.4). Compare against affected ranges: >= 1.8.0 and < 1.8.10, OR >= 1.9.0 and < 1.9.5.Affected if Version is between 1.8.0 and 1.8.9 inclusive, or between 1.9.0 and 1.9.4 inclusive
-
Verify audit logging is configuredCheck for audit log configuration in Consul configuration files (default location /opt/consul/config or as specified via CONSUL_CONFIG_DIR environment variable). Look for 'audit' block in JSON configuration files.Affected if Audit logging is enabled in the Consul configuration - the vulnerability only applies when audit logs are configured to record events
-
Check if audit logs are actively being writtenExamine the audit log directory as configured (typically under Consul data directory). Use 'ls -la' to verify log files exist and are being updated.Affected if Audit logs exist and are actively being written to, indicating audit logging is in use
You are affected if you run Consul Enterprise versions 1.8.0-1.8.9 or 1.9.0-1.9.4 with audit logging enabled, as attackers can bypass audit logging using crafted HTTP requests.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor data1.8.101.9.5
Upgrade Consul Enterprise to version 1.9.5, 1.8.10, or later to remediate the audit log bypass vulnerability.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-28156 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-28156 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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