lychee link checking action affected by arbitrary code injection in composite action
        
  Moderate severity
        
          GitHub Reviewed
      
        Published
          Aug 28, 2025 
          in
          
            lycheeverse/lychee-action
          
          •
          Updated Aug 28, 2025 
      
  
Description
        Published to the GitHub Advisory Database
      Aug 28, 2025 
    
  
        Reviewed
      Aug 28, 2025 
    
  
        Published by the National Vulnerability Database
      Aug 28, 2025 
    
  
        Last updated
      Aug 28, 2025 
    
  
Summary
There is a potential attack of arbitrary code injection vulnerability in
lychee-setupof the composite action at action.yml.Details
The GitHub Action variable
inputs.lycheeVersioncan be used to execute arbitrary code in the context of the action.PoC
The previous example will just print all the environment variables to the summary of the workflow, but an attacker could potentially use this vector to compromise the security of the target repository, even passing unnotice because the action will run normally.
Impact
Low
References