CVE-2025-11375
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 · uneditedConsul and Consul Enterprise’s (“Consul”) event endpoint is vulnerable to denial of service (DoS) due to lack of maximum value on the Content Length header. This vulnerability, CVE-2025-11375, is fixed in Consul Community Edition 1.22.0 and Consul Enterprise 1.22.0, 1.21.6, 1.20.8 and 1.18.12.
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 confidenceConsul's event endpoint lacks validation on the Content-Length HTTP header, allowing attackers to specify arbitrarily large values that can exhaust server resources and cause denial of service.
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< 1.18.12< 1.22.0>= 1.19.0, < 1.20.8>= 1.21.0, < 1.21.6CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Check if Consul is installed and runningRun `consul version` to verify the Consul binary exists, or check for the consul process using `ps aux | grep consul` or `systemctl status consul`Affected if Consul is not installed or not running - the check is not applicable
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Determine the installed Consul versionRun `consul version` to obtain the exact version number, or query the API endpoint `curl http://localhost:8500/v1/agent/self` to retrieve version information from the running agentAffected if The version output shows a version lower than 1.18.12, or between 1.19.0-1.20.7, or between 1.21.0-1.21.5, indicating the patch is not applied
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Verify the event endpoint is accessibleCheck if the Consul API is exposed by attempting a request to the event endpoint: `curl -X GET http://localhost:8500/v1/event/list` (adjust hostname/port if Consul listens on a different address)Affected if The endpoint responds successfully, meaning the Consul API is exposed over HTTP/HTTPS and could accept malicious Content-Length headers
You are affected if Consul is running with a version in the affected ranges (pre-1.18.12, 1.19.0-1.20.7, or 1.21.0-1.21.5) AND the Consul API event endpoint is accessible over the network.
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.
dbcve · scoped1.18.121.20.81.21.6
Upgrade Consul to version 1.22.0 (Community) or Enterprise versions 1.22.0, 1.21.6, 1.20.8, or 1.18.12 to apply the patch that introduces Content-Length header validation.
Consul Community Edition 1.22.0 or Enterprise 1.22.0/1.21.6/1.20.8/1.18.12 (choose the latest in your version branch)
- 1. Identify the current Consul version by running 'consul --version'
- 2. Determine the appropriate upgrade path based on your current version: if on 1.18.x upgrade to 1.18.12; if on 1.19.x or 1.20.x upgrade to 1.20.8; if on 1.21.x upgrade to 1.21.6; if on newer versions upgrade to 1.22.0
- 3. Review the Consul upgrade documentation at https://developer.hashicorp.com/consul/docs/upgrades
- 4. Create a backup of Consul data and configuration files before upgrading
- 5. Test the upgrade in a non-production environment first
- 6. Schedule a maintenance window for the production upgrade
- 7. Upgrade Consul binaries on all nodes following a rolling upgrade procedure
- 8. Verify the upgrade was successful by checking Consul functionality and checking the version with 'consul --version'
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 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 $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-11375 — 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-2025-11375 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
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- 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
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