NginxWeb server / proxy · F5
CVE-2018-16843
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 · uneditednginx before versions 1.15.6 and 1.14.1 has a vulnerability in the implementation of HTTP/2 that can allow for excessive memory consumption. This issue affects nginx compiled with the ngx_http_v2_module (not compiled by default) if the 'http2' option of the 'listen' directive is used in a configuration file.
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 confidencenginx versions before 1.15.6 and 1.14.1 contain a memory consumption vulnerability in the HTTP/2 implementation (ngx_http_v2_module). When the http2 option is enabled on a listen directive, specially crafted HTTP/2 requests can cause excessive memory allocation, potentially leading to 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
NginxWeb server / proxy
> 1.9.5, < 1.14.1> 1.15.0, < 1.15.6
Debian LinuxOperating system
= 9.0
Ubuntu LinuxOperating system
= 14.04= 16.04= 18.04= 18.10= 15.1< 13.0CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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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Determine installed nginx versionRun 'nginx -v' or 'nginx -V' to see the version. On some systems, check '/usr/sbin/nginx -v' or 'nginx -version'. Compare the version number against the affected ranges: versions 1.9.5 < x < 1.14.1 and 1.15.0 < x < 1.15.6 are vulnerable.Affected if The installed nginx version falls within 1.9.5 to 1.14.0 or 1.15.0 to 1.15.5.
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Verify HTTP/2 module is loadedRun 'nginx -V 2>&1 | grep -o http_v2_module' to check if the ngx_http_v2_module is compiled into the nginx binary. Alternatively, run 'nginx -M' to list loaded modules and look for 'http_v2' in the output.Affected if The ngx_http_v2_module is present in the nginx build.
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Inspect nginx configuration for HTTP/2 enabled listen directivesSearch all nginx configuration files (typically in /etc/nginx/, /etc/nginx/conf.d/, or /etc/nginx/sites-enabled/) for 'listen' directives that include the 'http2' option. Use: 'grep -r "listen.*http2" /etc/nginx/' or manually review configuration files.Affected if Any 'listen' directive contains 'http2' option, enabling the vulnerable code path.
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Check for active nginx processesRun 'ps aux | grep nginx' or 'systemctl status nginx' to confirm nginx is running. The vulnerability is only exploitable when nginx is actively processing requests.Affected if Nginx is running and serving traffic with HTTP/2 enabled.
If nginx version is between 1.9.5 and 1.14.0 or between 1.15.0 and 1.15.5, the http_v2_module is loaded, and any listen directive has http2 enabled, the environment is affected by this vulnerability.
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 data1.14.11.15.613.0
Upgrade nginx to version 1.15.6/1.14.1 or later. If upgrading is not immediately possible, disable HTTP/2 on affected listen directives or ensure the ngx_http_v2_module is not loaded.
Fix this in Nginx
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-16843 — 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-2018-16843 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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- Version or environment caveats, and links to real fixes
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