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May 14, 2024

GHSL-2024-044: GitHub Actions expression injection in Simple Icons

Jorge Rosillo

Coordinated Disclosure Timeline


Simple Icons is vulnerable to an Actions expression injection, allowing an attacker to take over the repository and steal secrets.


Simple Icons

Tested Version



Actions expression injection in autoclose-issues.yml (GHSL-2024-044)

The autoclose-issues.yml workflow is triggered on issue (i.e., when an Issue is created). The workflow starts with full write-permissions GitHub repository token since the default workflow permissions on Organization/Repository level are set to read-write.

Taking the above into account, this workflow injects data controlled by said Issue (${{ github.event.issue.title }} – the title of the Issue) into a Run step’s script, allowing an attacker to take over the GitHub Runner to run custom commands and alter the repository.

- id: match-java
  name: Match Java
  run: |
    if [[ "${{ github.event.issue.title }}" =~ (^|[[:space:]])([jJ][aA][vV][aA])([[:space:]]|$) ]]; then
        echo "match=true" >> $GITHUB_OUTPUT

This issue was found using CodeQL for JavaScript’s Expression injection in Actions query.


This issue may lead to stealing workflow secrets and modification of the repository.

Proof of Concept

  1. Open an Issue with the following title: $(whoami)
  2. Check the workflow runs for the new Actions run that will execute the command whoami.



This issue was discovered and reported by GHSL team member @jorgectf (Jorge Rosillo).


You can contact the GHSL team at, please include a reference to GHSL-2024-044 in any communication regarding this issue.