CVE Catalog

CVE-2026-55557

HighCVSS 8.6
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.19%

9th percentile - higher than 9% of all known CVEs

Summary

browse-mcp prior to 0.8.2 writes fetched response bodies to a caller-controlled save_dir without validation, while browser_save_state and browser_load_state honor a caller-controlled path unchanged. A malicious MCP client or an agent steered by indirect prompt injection can write files to any path the process can reach, including ~/.bashrc, autostart entries, or cron files, potentially leading to host code execution. This issue is fixed in version 0.8.2.

Risk Assessment

An attacker could write malicious files to critical system locations, potentially leading to host takeover or persistent security compromise.

Recommendation

It is recommended to upgrade browse-mcp to version 0.8.2. Also, restrict process privileges and avoid using untrusted MCP clients.

Related vulnerabilities

Original NVD description (English source)

browse-mcp is a Playwright-based headless-browser MCP server for MCP-capable agents. Prior to 0.8.2, browser_download writes a fetched response body to join(save_dir, filename) without validating the caller-controlled save_dir, while browser_save_state and browser_load_state honor a caller-controlled path unchanged. A malicious MCP client, or an autonomous agent steered by indirect prompt injection on a visited page, can choose an arbitrary save_dir or state path and a URL whose response body becomes attacker-controlled file contents, allowing writes to any path the process can reach, including ~/.bashrc, autostart entries, or cron files, and potentially leading to host code execution. The force_fetch fallback also uses a raw fetch() that bypasses the BROWSE_MCP_ALLOWED_ORIGINS origin fence. This issue is fixed in version 0.8.2.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS