CVE-2026-56236: Capgo CLI Symlink Vulnerability – Credential Exposure & File Overwrite Risk

Technical summary

CVE-2026-56236 is a symlink-following vulnerability in Capgo CLI prior to version 12.128.2. The vulnerability exists in the login and build credential operations, where the CLI fails to validate symlink targets before performing file write operations. This allows an attacker to craft a malicious repository containing symlinks that redirect credential writes to arbitrary filesystem locations. The resulting files may be created with overly permissive permissions (world-readable), enabling local privilege escalation and credential disclosure. The vulnerability is classified under CWE-59 (Improper Link Resolution Before File Access, also known as 'Link Following').

Business impact

Development teams using Capgo CLI are at risk of credential compromise and system integrity violations. If a developer clones a malicious repository and runs the CLI, an attacker can steal API keys, authentication tokens, or other secrets written to credential files. Additionally, symlink-based overwrites could corrupt build artifacts, configuration files, or other critical files in the developer's workspace. This impacts the supply chain: compromised credentials could be leveraged to push malicious code, modify deployments, or access production systems. Organizations relying on Capgo for app building and deployment should treat credential exposure as a breach event and initiate secret rotation.

Affected systems

Capgo CLI versions prior to 12.128.2 are affected. Any developer or CI/CD pipeline using an unpatched version is at risk, particularly those working with untrusted or user-contributed repositories. The vulnerability requires local code execution (developer running the CLI), so exposure is primarily to internal development teams and build infrastructure.

Exploitability

Exploitability requires user interaction—a developer must run the affected CLI against a malicious repository. An attacker cannot remotely trigger the vulnerability without repository access and developer action. However, the attack surface is moderately broad: any repository (GitHub, GitLab, internal git servers) could be weaponized. Since developers often work with third-party dependencies and may clone unfamiliar repositories during development, the practical exploitability is elevated in open-source and collaborative environments. No patch bypass or complex exploitation techniques are required; creating a symlink and waiting for a developer to run the CLI is straightforward.

Remediation

Upgrade Capgo CLI to version 12.128.2 or later. This version addresses the symlink validation issue by properly resolving and validating symlink targets before performing credential file writes. Organizations should establish a policy requiring developers to use the patched version and enforce it via dependency management tools. Additionally, conduct a credentials audit: any developer who ran an unpatched version against unknown repositories should rotate API keys, tokens, and other secrets stored in Capgo credential files.

Patch guidance

Users should update Capgo CLI to version 12.128.2 or later. Verify the upgrade by running the CLI with a --version flag to confirm the installed version. If using Capgo in a CI/CD pipeline (GitHub Actions, GitLab CI, etc.), update the action or tool version in your workflow configuration. For teams managing multiple developers, enforce version constraints in package management files (npm, yarn, pip, etc.) and use dependency scanning tools to detect outdated versions. Test the patched version in a non-production environment before rolling out to development teams to rule out compatibility issues.

Detection guidance

Monitor for suspicious symlink creation in repositories, particularly in .git directories or credential storage paths. Log CLI invocations and track which repositories are accessed. Implement file integrity monitoring on developer machines and build servers to detect unexpected file overwrites or permission changes in credential directories (e.g., ~/.capgo or equivalent). Review audit logs for credential file access: world-readable credential files are a red flag. For CI/CD environments, audit workflow logs for CLI version usage and flag any builds using versions prior to 12.128.2.

Why prioritize this

Although not yet listed in CISA's Known Exploited Vulnerabilities catalog, this vulnerability should be prioritized due to its impact on credential security and supply chain risk. The CVSS score of 6.1 (MEDIUM) reflects the need for local user interaction, but the consequence—credential exposure—is severe. Development teams and DevOps personnel should apply the patch within 1–2 weeks. Organizations handling sensitive deployments or working with untrusted external contributors should prioritize faster.

Risk score, explained

The CVSS 3.1 score of 6.1 (MEDIUM) is driven by: local attack vector (AV:L), requiring no special privileges (PR:N), and user interaction (UI:R). The integrity impact is high (I:H) because attackers can overwrite files; confidentiality is low (C:L) because credential files are typically readable by the user context; and availability is none (A:N). The score appropriately reflects the real-world risk: a developer must run the CLI, but when they do, the impact is material. Organizations with stricter credentials policies or air-gapped development may assess risk as lower; those accepting external contributions assess it as higher.

Frequently asked questions