Out-of-bounds Read Affecting fast-string-search Open this link in a new tab package, versions *

  • Exploit Maturity

    Proof of concept

  • Attack Complexity


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  • snyk-id


  • published

    16 Jun 2022

  • disclosed

    3 Feb 2022

  • credit

    Cristian-Alexandru Staicu

How to fix?

There is no fixed version for fast-string-search.


fast-string-search is a module that can search substrings in a string by using N-API and boyer-moore-magiclen.

Affected versions of this package are vulnerable to Out-of-bounds Read due to incorrect memory freeing and length calculation for any non-string input as the source. This allows the attacker to read previously allocated memory.


const fss = require('fast-string-search');
fss.indexOf("My password is joke 9", "is"); 
let res = fss.indexOf(1, "9"); 
// res will contain the index of "9" from the previous input and not the current one.