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Critical, CVSS 9.1amended

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

CVE-2025-9287GHSA-cpq7-6gpm-g9rc

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (cipher-base 1.0.5), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
9.1 · 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 · score source
EPSS
  • CVE-2025-9287: 0.55% estimated exploitation activity in the next 30 days; percentile 46.08 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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 Output: This works with: 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…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-cpq7-6gpm-g9rc

  2. Revision 2 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 1 · created ·

    Published from osv record GHSA-cpq7-6gpm-g9rc

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2025-9287

Advisory: cipher-base is missing type checks, leading to hash rewind and passing on crafted data
IDs: CVE-2025-9287, GHSA-cpq7-6gpm-g9rc
Record: https://patchnext.com/advisories/cve-2025-9287 (revision 3, source checked 26 Oct 2026, 12:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: cipher-base 1.0.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm cipher-base: affected <= 1.0.4; fixed in 1.0.5

## Suggested inspection (read-only)
- `npm ls cipher-base --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on cipher-base.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-cpq7-6gpm-g9rc (OSV record GHSA-cpq7-6gpm-g9rc lists affected ranges: npm cipher-base >=0 <1.0.5 (fixed))
- Verified: https://github.com/advisories/GHSA-cpq7-6gpm-g9rc (GitHub-reviewed advisory GHSA-cpq7-6gpm-g9rc lists affected ranges: npm cipher-base >=0 <=1.0.4)

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