{"cve":"CVE-2026-55557","nvd":{"published":"2026-08-25T17:17:32.357","modified":"2026-09-09T21:07:31.353","status":"Deferred","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.","cvss_v4":{"vector":"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","score":8.6},"cvss_v3":null,"cwes":["CWE-22"],"references":["https://github.com/That1Drifter/browse-mcp/blob/v0.8.2/CHANGELOG.md#082---2026-06-13","https://github.com/That1Drifter/browse-mcp/commit/5352a4a56f626254b445bfa07e4bb48c5aad15c1","https://github.com/That1Drifter/browse-mcp/pull/58","https://github.com/That1Drifter/browse-mcp/releases/tag/v0.8.2","https://github.com/That1Drifter/browse-mcp/security/advisories/GHSA-m9mq-7m7q-xc6p"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-55557","score":0.00238,"percentile":0.14928,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-m9mq-7m7q-xc6p","url":"https://osv.dev/vulnerability/GHSA-m9mq-7m7q-xc6p","summary":"browse-mcp has an arbitrary file write via unconfined download and state paths","modified":"2026-08-26T00:05:58.828785060Z","packages":[{"ecosystem":"npm","name":"browse-mcp","purl":"pkg:npm/browse-mcp","ranges":["<0.8.2"],"fixed":["0.8.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}