{"data":{"id":"3ae00be3-20e2-41ae-a425-6c3e2bb5f4d8","title":"GHSA-m9mq-7m7q-xc6p: browse-mcp has an arbitrary file write via unconfined download and state paths","summary":"browse-mcp, an MCP server, has an arbitrary file write flaw in `browser_download`, `browser_save_state` and `browser_load_state`. Their `save_dir` and `path` arguments are not validated, so a caller controlling the MCP arguments can write attacker-supplied response bytes to any path the process can reach, such as `~/.bashrc` or a cron file, which can lead to host code execution. The `force_fetch` fallback also bypassed the `BROWSE_MCP_ALLOWED_ORIGINS` origin fence. The estimated CVSS 3.1 score is around 7.8 (High) for the local, agent-mediated case.","solution":"Fixed in 0.8.2. Upgrade to browse-mcp 0.8.2. The fix confines `save_dir` under `~/.browse-mcp/downloads` and the state `path` under `~/.browse-mcp/state`, rejects absolute paths and `..` escapes, reduces download filenames to a bare basename, and makes `force_fetch` honor the origin fence. Workaround: restrict `BROWSE_MCP_TOOLS` to exclude `browser_download`, `browser_save_state` and `browser_load_state`, noting this does not stop a malicious MCP client from calling them by name.","labels":["security"],"sourceUrl":"https://github.com/advisories/GHSA-m9mq-7m7q-xc6p","publishedAt":"2026-08-25T16:28:32.000Z","cveId":"CVE-2026-55557","cweIds":null,"cvssScore":null,"cvssSeverity":"high","severity":"high","attackType":["other"],"issueType":"vulnerability","affectedPackages":["browse-mcp@<= 0.8.1 (fixed: 0.8.2)"],"affectedPackageNames":["browse-mcp"],"affectedPackageRefs":["npm:browse-mcp"],"affectedVendors":[],"affectedVendorsRaw":["browse-mcp","MCP"],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":null,"headlinePromptVersion":null,"cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":"unknown","epssScore":0.00238,"epssCheckedAt":"2026-11-04T06:10:13.969Z","kevDateAdded":null,"advisoryAliases":["GHSA-m9mq-7m7q-xc6p"],"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":true,"disclosureDate":"2026-08-25T16:28:32.000Z","fixReleasedAt":"2026-06-13T16:23:58.907Z","daysToFix":-73,"fixCheckedAt":"2026-10-29T21:31:11.217Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["integrity","confidentiality"],"aiComponentTargeted":"plugin","llmSpecific":false,"classifierConfidence":0.9,"researchCategory":null,"atlasIds":null,"fixes":[{"ecosystem":"npm","name":"browse-mcp","fixedVersion":"0.8.2","matchedVersion":"0.8.2","fixReleasedAt":"2026-06-13T16:23:58.907Z","daysToFix":-73,"match":"ecosystem","source":"registry","status":"found","checkedAt":"2026-10-29T21:31:11.071Z"}]}}