{"id":"CVE-2026-55557","title":"browse-mcp is a Playwright-based headless-browser MCP server for MCP-capable agents","summary":"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 bro…","severity":"high","cwe":["CWE-22"],"vendor":"browse-mcp","product":"browse-mcp","affected":["browse-mcp <= 0.8.1"],"patched":["browse-mcp 0.8.2"],"published":"2026-08-25","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:07:31.353","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55557","references":[{"url":"https://github.com/That1Drifter/browse-mcp/blob/v0.8.2/CHANGELOG.md#082---2026-06-13","label":"security-advisories@github.com"},{"url":"https://github.com/That1Drifter/browse-mcp/commit/5352a4a56f626254b445bfa07e4bb48c5aad15c1","label":"security-advisories@github.com"},{"url":"https://github.com/That1Drifter/browse-mcp/pull/58","label":"security-advisories@github.com"},{"url":"https://github.com/That1Drifter/browse-mcp/releases/tag/v0.8.2","label":"security-advisories@github.com"},{"url":"https://github.com/That1Drifter/browse-mcp/security/advisories/GHSA-m9mq-7m7q-xc6p","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-m9mq-7m7q-xc6p"}],"tags":["nvd","ghsa","npm"],"epss":0.00189,"epssPercentile":0.0874,"aliases":["GHSA-m9mq-7m7q-xc6p"],"ecosystem":"npm","ingestedAt":"2026-08-25T17:29:32.244Z","slug":"CVE-2026-55557","body":"## Overview\n\nbrowse-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-55557)\n\nAffected packages:\n\n- `browse-mcp <= 0.8.1`\n\nPatched in:\n\n- `browse-mcp 0.8.2`\n\nSource: https://github.com/advisories/GHSA-m9mq-7m7q-xc6p","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}