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A File Format to Aid in Security Vulnerability Disclosure
Security txt.png
Example security.txt file
Year started2017
First publishedSeptember 2017
Latest version12
11 March 2021
AuthorsEdwin Foudil

security.txt is a proposed standard for websites' security information that is meant to allow security researchers to easily report security vulnerabilities.[1][2] The standard prescribes a text file called "security.txt" in the well known location, similar in syntax to robots.txt but intended to be machine- and human-readable, for those wishing to contact a website's owner about security issues.[3] security.txt files have been adopted by Google, GitHub, LinkedIn, and Facebook.[4]


The Internet Draft was first submitted by Edwin Foudil in September 2017.[1] At that time it covered four directives, "Contact", "Encryption", "Disclosure" and "Acknowledgement". Foudil expected to add further directives based on feedback.[2] In addition, web security expert Scott Helme said he had seen positive feedback from the security community while use among the top 1 million websites was "as low as expected right now".[1]

In 2019, the Cybersecurity and Infrastructure Security Agency (CISA) published a draft binding operational directive that requires all federal agencies to publish a security.txt file within 180 days.[5][6]

The Internet Engineering Steering Group (IESG) issued a Last Call for security.txt in December 2019 which ended on January 6, 2020.[7]

A study in 2021 found that over ten percent of top-100 websites published a security.txt file, with the percentage of sites publishing the file decreasing as more websites were considered.[8] The study also noted a number of discrepancies between the standard and the content of the file.

In April 2022 the security.txt file has been accepted by Internet Engineering Task Force (IETF) as RFC 9116.[9]

File format[edit]

security.txt files can be served under the /.well-known/ directory (i.e. /.well-known/security.txt) or the top-level directory (i.e. /security.txt) of a website. The file must be served over HTTPS and in plaintext format.[10]

See also[edit]


  1. ^ a b c at 13:47, John Leyden 3 Jan 2018. "Bug-finders' scheme: Tick-tock, this tech's tested by flaws.. but who the heck do you tell?". Retrieved 2019-04-14.
  2. ^ a b "Security.txt Standard Proposed, Similar to Robots.txt". BleepingComputer. Retrieved 2019-04-14.
  3. ^ "The Telltale Text File: Security Researcher Proposes Standard for Reporting Vulnerabilities". Security Intelligence. Retrieved 2019-04-14.
  4. ^ Cimpanu, Catalin (2019-11-29). "iOS apps could really benefit from the newly proposed Security.plist standard". ZDNet. Retrieved 2020-06-16.
  5. ^ "CISA Seeks Comments on How Government Should Handle Vulnerability Reports". Decipher. Retrieved 2020-01-29.
  6. ^ Kuldell, Heather (2019-12-18). "CISA Still Wants Your Thoughts on Its Vulnerability Disclosure Policy". Retrieved 2020-01-29.
  7. ^ "Security.txt – IESG issues final call for comment on proposed vulnerability reporting standard". The Daily Swig | Cybersecurity news and views. 2019-12-12. Retrieved 2020-03-30.
  8. ^ Poteat, Tara; Li, Frank (November 2021). "Who you gonna call?: an empirical evaluation of website security.txt deployment". IMC '21: Proceedings of the 21st ACM Internet Measurement Conference. Internet Measurement Conference. Online: ACM. pp. 526–532. doi:10.1145/3487552.3487841.
  9. ^ Foudil, Edwin; Shafranovich, Yakov (April 2022). "RFC 9116 – A File Format to Aid in Security Vulnerability Disclosure".
  10. ^ "Characterizing the Adoption of Security.txt Files" (PDF). Characterizing the Adoption of Security.txt Files. 2022-02-11. Retrieved 2022-03-01.

External links[edit]