Nuclie – Massive Vulnerability Scanner

Nuclie – Massive Vulnerability Scanner


Nuclei is a fast tool for configurable targeted scanning based on templates offering massive extensibility and ease of use.

Nuclei is used to send requests across targets based on a template leading to zero false positives and providing effective scanning for known paths. Main use cases for nuclei are during initial reconnaissance phase to quickly check for low hanging fruits or CVEs across targets that are known and easily detectable. It uses retryablehttp-go library designed to handle various errors and retries in case of blocking by WAFs, this is also one of our core modules from custom-queries.

We have also open-sourced a template repository to maintain various type of templates, we hope that you will contribute there too. Templates are provided in hopes that these will be useful and will allow everyone to build their own templates for the scanner. Checkout the templating guide at for a primer on nuclei templates.



  • Simple and modular code base making it easy to contribute.
  • Fast And fully configurable using a template based engine.
  • Handles edge cases doing retries, backoffs etc for handling WAFs.
  • Smart matching functionality for zero false positive scanning.


nuclei -h

This will display help for the tool. Here are all the switches it supports.

bulk-sizeMax hosts analyzed in parallel per template ( default 25)nuclei -bulk-size 25
burp-collaborator-biidBurp Collaborator BIIDnuclei -burp-collaborator-biid XXXX
cMax templates processed in parallel (default 10)nuclei -c 10
lList of urls to run templatesnuclei -l urls.txt
targetTarget to scan using Templatesnuclei -target hxxps://
tTemplates input file/files to check across hostsnuclei -t git-core.yaml -t cves/
no-colorDon’t Use colors in outputnuclei -no-color
no-metaDon’t display metadata for the matchesnuclei -no-meta
jsonPrints and write output in json formatnuclei -json
include-rrInlcude req/resp of matched output in JSON outputnuclei -json -include-rr
oFile to save output result (optional)nuclei -o output.txt
projectProject flag to avoid sending same requestsnuclei -project
project-pathUse a user defined project foldernuclei -project -project-path test
statsEnable the progress bar (optional)nuclei -stats
silentShow only found results in outputnuclei -silent
retriesNumber of times to retry a failed requestnuclei -retries 1
timeoutSeconds to wait before timeout (default 5)nuclei -timeout 5
trace-logFile to write sent requests trace lognuclei -trace-log logs
rate-limitMaximum requests/second (default 150)nuclei -rate-limit 150
severityRun templates based on severitynuclei -severity critical,high
stop-at-first-matchStop processing http requests at first matchnuclei -stop-at-first-match
excludeTemplate input dir/file/files to excludenuclei -exclude panels -exclude tokens
debugAllow debugging of request/responses.nuclei -debug
update-templatesDownload and updates nuclei templatesnuclei -update-templates
update-directoryDirectory for storing nuclei-templates(optional)nuclei -update-directory templates
tlList available templatesnuclei -tl
templates-versionShows the installed nuclei-templates versionnuclei -templates-version
vShows verbose output of all sent requestsnuclei -v
versionShow version of nucleinuclei -version
proxy-urlProxy URLnuclei -proxy-url hxxp://
proxy-socks-urlSocks proxyURLnuclei -proxy-socks-url socks5://
random-agentUse random User-Agentsnuclei -random-agent
HCustom Headernuclei -H “x-bug-bounty: hacker”

Installation Instructions

From Binary

The installation is easy. You can download the pre-built binaries for your platform from the Releases page. Extract them using tar, move it to your $PATHand you’re ready to go.

Download latest binary from

▶ tar -xzvf nuclei-linux-amd64.tar.gz
▶ mv nuclei /usr/local/bin/
▶ nuclei -version

From Source

nuclei requires go1.14+ to install successfully. Run the following command to get the repo –

▶ GO111MODULE=on go get -u -v

From Github

▶ git clone; cd nuclei/v2/cmd/nuclei/; go build; mv nuclei /usr/local/bin/; nuclei -version

Nuclei templates

You can download or update the nuclei templates using update-templates flag.

▶ nuclei -update-templates

or download it from nuclei templates Github project.

▶ git clone

Please refer to nuclei templating guide to writing your own custom templates.

Running Nuclei

Running with single template.

This will run git-core.yaml template against all the hosts in urls.txt and returns the matched results.

▶ nuclei -l urls.txt -t files/git-core.yaml -o results.txt

You can also pass the list of urls at standard input (STDIN). This allows for easy integration in automation pipelines.

▶ cat urls.txt | nuclei -t files/git-core.yaml -o results.txt

bulb Nuclei accepts list of URLs as input, for example here is how urls.txt looks like:-

Running with multiple templates.

This will run the tool against all the urls in urls.txt with all the templates in the cves and files directory and returns the matched results.

▶ nuclei -l urls.txt -t cves/ -t files/ -o results.txt

Running with subfinder.

▶ subfinder -d -silent | httpx -silent | nuclei -t cves/ -o results.txt

Running in Docker container

You can use the nuclei dockerhub image. Simply run –

▶ docker pull projectdiscovery/nuclei

After downloading or building the container, run the following:

▶ docker run -it projectdiscovery/nuclei

For example, this will run the tool against all the hosts in urls.txt and output the results to your host file system:

▶ cat urls.txt | docker run -v /path/to/nuclei-templates:/app/nuclei-templates -v /path/to/nuclei/config:/app/.nuclei-config.json -i projectdiscovery/nuclei -t /app/nuclei-templates/files/git-config.yaml > results.txt

Remember to change /path-to-nuclei-templates to the real path on your host file system.

Rate Limits

Nuclei have multiple rate limit controls for multiple factors including a number of templates to execute in parallel, a number of hosts to be scanned in parallel for each template, and the global number of request / per second you wanted to make/limit using nuclei, as an example here is how all this can be controlled using flags.

  • -c flag => Limits the number of templates processed in parallel.
  • -bulk-size flag => Limits the number of hosts processed in parallel for each template.
  • -rate-limit flag => Global rate limiter that ensures defined number of requests/second across all templates.

If you wanted go fast or control the scans, feel free to play with these flags and numbers, rate-limit always ensure to control the outgoing requests regardless the other flag you are using.

Template Exclusion

Nuclei-templates includes multiple checks including many that are useful for attack surface mapping and not necessarily a security issue, in cases where you only looking to scan few specific templates or directory, here are few options / flags to filter or exclude them from running.

Running templates with exclusion

We do not suggest running all the nuclei-templates directory at once, in case of doing so, one can make use of exclude flag to exclude specific directory or templates to ignore from scanning.

nuclei -l urls.txt -t nuclei-templates -exclude panels/ -exclude technologies -exclude files/wp-xmlrpc.yaml

Note:- both directory and specific templates case be excluded from scan as shared in the above example.

Running templates based on severity

You can run the templates based on the specific severity of the template, single and multiple severity can be used for scan.

nuclei -l urls.txt -t cves/ -severity critical,medium

The above example will run all the templates under cves directory with critical and medium severity.

nuclei -l urls.txt -t panels/ -t technologies -severity info

The above example will run all the templates under panels and technologies directory with severity marked as info

Using .nuclei-ignore file for template exclusion

Since release of nuclei v2.1.1, we have added support of .nuclei-ignore file that works along with update-templates flag of nuclei, in .nuclei-ignore file, you can define all the template directory or template path that you wanted to exclude from all the nuclei scans, to start using this feature, make sure you installed nuclei templates using nuclei -update-templates flag, now you can add/update/remove templates in the file that you wanted to exclude from running.

nano ~/nuclei-templates/.nuclei-ignore

Default nuclei-ignore list can be accessed from here, in case you don’t want to exclude anything, simply remove the .nuclei-ignore file.

clipboard Notes

  • Progress bar is experimental feature, might not work in few cases.
  • Progress bar doesn’t work with workflows, numbers are not accurate due to conditional execution.



nuclei is made with black_heart by the projectdiscovery team. Community contributions have made the project what it is. See the file for more details.

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