CVE-2026-55557

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Source

https://cve.org/CVERecord?id=CVE-2026-55557

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55557.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-55557

Aliases

GHSA-m9mq-7m7q-xc6p

Published

2026-08-25T16:28:07Z

Modified

2026-09-11T03:30:56Z

Severity

8.6 (High) CVSS_V4 - 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 CVSS Calculator

Summary

browse-mcp: Arbitrary file write via unconfined download and state paths

Details

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.

Database specific

{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-22"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55557.json"
}

References

Affected packages

Git / github.com/that1drifter/browse-mcp

Affected ranges

Type

GIT

Repo

https://github.com/that1drifter/browse-mcp

Events

Introduced

Fixed

5352a4a56f626254b445bfa07e4bb48c5aad15c1

Fixed

46d75f467d1a8f3c88b7224eacfd4038a969e7e8

Database specific

Show details

{
    "extracted_events":  [
        {
            "introduced":  "0"
        },
        {
            "fixed":  "0.8.2"
        }
    ],
    "source":  [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

v0.*

v0.2.1

v0.3.0

v0.4.0

v0.4.1

v0.5.0

v0.6.0

v0.7.0

v0.8.0

v0.8.1

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55557.json"