CVE-2026-55675 in docs
Summary
by MITRE • 10/13/2026
The Salty documentation repository builds and deploys the docs.saltbox.dev website. Prior to commit 649c9aea2daef1168eeb0415b44e65dbbde9f220, .github/workflows/trigger-pr-build.yml records an untrusted fork commit in the pr_info artifact, and the secret-bearing workflow_run job in .github/workflows/build-pr.yml checks out that commit before running pip install -r requirements.txt. A fork pull request can therefore supply attacker-authored setup.py or PEP 517 build hooks whose installation code executes in the privileged base-repository workflow with CF_API_TOKEN, GH_TOKEN, MKDOCS_GIT_COMMITTERS_APIKEY, and a write-capable GITHUB_TOKEN, allowing secret disclosure and follow-on compromise. The vulnerability is not caused by the repository-fork guard, and the demonstrated path requires attacker control of fork content rather than merely the artifact metadata. This vulnerability is fixed with commit 649c9aea2daef1168eeb0415b44e65dbbde9f220.
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Analysis
by VulDB Data Team • 10/13/2026
The described vulnerability represents a critical supply chain attack vector within the GitHub Actions CI/CD pipeline of the Salty documentation repository, specifically targeting the automated build and deployment process for docs.saltbox.dev. The core issue stems from an insecure handling of untrusted input in the workflow definition files, particularly involving pull requests originating from external forks. Prior to the remediation commit 649c9aea2daef1168eeb0415b44e65dbbde9f220, the workflow file trigger-pr-build.yml was configured to capture and store information about incoming pull request commits in an artifact named pr_info. This artifact contained metadata regarding the commit SHA from a forked repository without sufficient validation or sanitization of its origin relative to trusted branches.
The severity of this flaw is amplified by how subsequent workflows consumed this data. The workflow build-pr.yml utilized a workflow_run trigger that depended on the output of the previous step. Crucially, it checked out and executed code based on the commit SHA recorded in the pr_info artifact from an untrusted fork. This action effectively allowed arbitrary code execution within the context of the base repository's privileged environment. When pip install -r requirements.txt was executed during this process, if the attacker-controlled setup.py file or PEP 517 build hooks contained malicious scripts, those scripts would run with elevated privileges inherent to GitHub Actions runners.
The operational impact is severe due to the exposure of sensitive secrets and credentials stored as repository-level environment variables. The privileged workflow context had access to CF_API_TOKEN for Cloudflare API operations, GH_TOKEN for GitHub interactions, MKDOCS_GIT_COMMITTERS_APIKEY for documentation publishing, and a write-capable GITHUB_TOKEN. An attacker could exploit this by submitting a pull request from a fork containing malicious Python package configuration files that execute arbitrary commands during the dependency installation phase. This allows for the exfiltration of these secrets to an external server controlled by the adversary, leading to potential account takeover, unauthorized modifications to the live documentation site via Cloudflare or MkDocs APIs, and further compromise of the repository's integrity through the write-capable token.
This vulnerability aligns with CWE-94 Improper Control of Generation of Code (Code Injection) as it involves executing untrusted code within a trusted environment. Furthermore, from an ATT&CK perspective, this maps to T1059 Command and Scripting Interpreter for initial execution via the Python interpreter during pip install, and potentially T1078 Valid Accounts if the stolen tokens are used to authenticate against other services or repositories. The flaw is not merely a metadata manipulation issue but requires active control over fork content, highlighting that attackers must inject malicious artifacts into the supply chain rather than just manipulating workflow variables.
Mitigation strategies involve strictly enforcing branch protection rules and restricting which workflows can be triggered by pull requests from forks. GitHub Actions best practices dictate using read-only tokens for PR builds whenever possible to limit the blast radius of any potential compromise. Additionally, input validation should be implemented to ensure that only commits from trusted branches or verified contributors are processed in privileged contexts. The vulnerability was addressed in commit 649c9aea2daef1168eeb0415b44e65dbbde9f220 by modifying the workflow logic to prevent the checkout and execution of untrusted fork code within the secret-bearing environment, thereby neutralizing the attack path.