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
Published
2026-08-25T16:28:07Z
Modified
2026-10-28T02:30:28Z
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
0 Unknown introduced commit / All previous commits are affected
Fixed
46d75f467d1a8f3c88b7224eacfd4038a969e7e8
Fixed
5352a4a56f626254b445bfa07e4bb48c5aad15c1
Database specific
Show details 
{
    "extracted_events": [
        {
            "range": [
                {
                    "introduced": "0"
                },
                {
                    "fixed": "0.8.2"
                }
            ],
            "source": "AFFECTED_FIELD",
            "strategy": "StringRangeExpression"
        },
        {
            "range": [
                {
                    "fixed": "5352a4a56f626254b445bfa07e4bb48c5aad15c1"
                }
            ],
            "source": "REFERENCES_COMMIT"
        },
        {
            "original_tag": "v0.8.2",
            "range": [
                {
                    "fixed": "46d75f467d1a8f3c88b7224eacfd4038a969e7e8"
                }
            ],
            "source": "REFERENCES_TAG"
        }
    ]
}

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"