RUSTSEC-2026-0140 (CVE-2026-42559)

Vulnerability from osv_rustsec – Published: 2026-05-12 12:00 – Updated: 2026-05-19 05:50 – Source website
VLAI
Summary
DNS rebinding and cross-origin CSRF in dynoxide's MCP HTTP transport
Details

dynoxide's MCP HTTP transport was vulnerable to DNS rebinding via its transitive rmcp dependency, plus a related cross-origin CSRF gap.

A malicious web page could make the user's browser send requests to a local dynoxide mcp --http or dynoxide serve --mcp server with a non-loopback Host header, which the server would then process. The Host check alone did not close a related cross-origin CSRF vector: a page could fetch the loopback endpoint with mode: 'no-cors', and the Host header would match while the Origin header went unchecked.

Affected MCP write tools include put_item, update_item, delete_item, create_table, and batch_write_item.

The stdio transport (dynoxide mcp without --http) is not affected.

Patches

dynoxide 0.9.13 closes both vectors:

  • Upgrades rmcp from 1.1.1 to 1.6.0 (which ships a default Host-header allowlist).
  • Sets explicit allowed_hosts and allowed_origins on StreamableHttpServerConfig.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "categories": [],
        "cvss": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "dynoxide-rs",
        "purl": "pkg:cargo/dynoxide-rs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.9.3"
            },
            {
              "fixed": "0.9.13"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2026-42559",
    "GHSA-89vp-x53w-74fx",
    "GHSA-fvh2-gm75-j4j7"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "dynoxide\u0027s MCP HTTP transport was vulnerable to DNS rebinding via its transitive `rmcp` dependency, plus a related cross-origin CSRF gap.\n\nA malicious web page could make the user\u0027s browser send requests to a local `dynoxide mcp --http` or `dynoxide serve --mcp` server with a non-loopback `Host` header, which the server would then process. The Host check alone did not close a related cross-origin CSRF vector: a page could `fetch` the loopback endpoint with `mode: \u0027no-cors\u0027`, and the Host header would match while the Origin header went unchecked.\n\nAffected MCP write tools include `put_item`, `update_item`, `delete_item`, `create_table`, and `batch_write_item`.\n\nThe stdio transport (`dynoxide mcp` without `--http`) is not affected.\n\n## Patches\n\ndynoxide 0.9.13 closes both vectors:\n\n- Upgrades `rmcp` from 1.1.1 to 1.6.0 (which ships a default Host-header allowlist).\n- Sets explicit `allowed_hosts` and `allowed_origins` on `StreamableHttpServerConfig`.",
  "id": "RUSTSEC-2026-0140",
  "modified": "2026-05-19T05:50:44Z",
  "published": "2026-05-12T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/dynoxide-rs"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0140.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/nubo-db/dynoxide/security/advisories/GHSA-fvh2-gm75-j4j7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nubo-db/dynoxide/releases/tag/v0.9.13"
    }
  ],
  "related": [
    "GHSA-89vp-x53w-74fx"
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "DNS rebinding and cross-origin CSRF in dynoxide\u0027s MCP HTTP transport"
}



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