Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-55557— browse-mcp: Arbitrary file write via unconfined download and state paths

Quick assessment

Affected
That1Drifter browse-mcp
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

是一个基于 Playwright 的、面向支持 MCP（Model Context Protocol）代理的无头浏览器 MCP 服务器。在 0.8.2 版本之前， 函数在将获取到的响应体写入 时，未对调用者可控的 参数进行有效验证；同时， 和 也直接使用了调用者可控的路径，未做任何修改或校验。 因此，恶意 MCP 客户端，或由访问页面中的间接提示注入（indirect prompt injection）所控制的自主代理，可以任意指定 或状态文件路径，并选择一个响应体内容可控的 URL，从而向进程可访问的任意路径写入

CVSS 8.6 · High

Affected Version Matrix 1

VendorProduct Version RangeStatus
That1Drifter browse-mcp < 0.8.2 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-55557

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
browse-mcp: Arbitrary file write via unconfined download and state paths
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
That1Drifter browse-mcp < 0.8.2 -

II. Public POCs for CVE-2026-55557

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 8305 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-55557

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-55557 (3)

Vendor Advisories for CVE-2026-55557 (2)

IV. Related Vulnerabilities

Same weakness: CWE-22

V. Comments for CVE-2026-55557

No comments yet

Leave a comment