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
2026-08-25T16:28:07.368Z
Modified
2026-08-27T11:47:40.307719092Z
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, browserdownload writes a fetched response body to join(savedir, filename) without validating the caller-controlled savedir, while browsersavestate and browserloadstate 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 savedir 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 forcefetch fallback also uses a raw fetch() that bypasses the BROWSEMCPALLOWEDORIGINS origin fence. This issue is fixed in version 0.8.2.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55557.json",
    "cwe_ids": [
        "CWE-22"
    ],
    "cna_assigner": "GitHub_M"
}
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
5352a4a56f626254b445bfa07e4bb48c5aad15c1
Fixed
46d75f467d1a8f3c88b7224eacfd4038a969e7e8
Database specific
Show details 
{
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "0.8.2"
        }
    ]
}

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"