{"apiVersion":"1.0","identifier":"CVE-2026-55557","description":"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.","publishedAt":"2026-08-25T17:17:32","lastModifiedAt":"2026-08-25T19:16:49","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55557","cvssScore":8.6,"cvssVector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","epssProbability":0.00189,"riskScore":0.87,"affectedProduct":"browse-mcp","affectedVersions":"<0.8.2","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-55557","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-55557","en":"https://www.redsauce.net/en/cves/CVE-2026-55557","fr":"https://www.redsauce.net/fr/cves/CVE-2026-55557","pt":"https://www.redsauce.net/pt/cves/CVE-2026-55557","de":"https://www.redsauce.net/de/cves/CVE-2026-55557","sk":"https://www.redsauce.net/sk/cves/CVE-2026-55557","el":"https://www.redsauce.net/el/cves/CVE-2026-55557"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-55557"}}