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High, CVSS 7.1amended

Prototype Pollution in JSON5 via Parse Method

CVE-2022-46175GHSA-9c47-m6qq-7p4h

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (json5 2.2.2, 1.0.2), 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

  • npm json5

    Affected
    >= 2.0.0, < 2.2.2< 1.0.2
    Fixed in
    1.0.2, 2.2.2

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.1 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:H
EPSS
  • CVE-2022-46175: 9.70% estimated exploitation activity in the next 30 days; percentile 95.52 (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.

The parse method of the JSON5 library before and including version 2.2.1 does not restrict parsing of keys named proto, allowing specially crafted strings to pollute the prototype of the resulting object. This vulnerability pollutes the prototype of the object returned by JSON5.parse and not the global Object prototype, which is the commonly understood definition of Prototype Pollution. However, polluting the prototype of a single object can have significant security impact for an application if the object is later used in trusted operations. Impact This vulnerability could allow an attacker to set arbitrary and unexpected keys on the object returned from JSON5.parse. The actual impact will depend on how applications utilize the returned object and how they filter unwanted keys, but could include denial of service, cross-site scripting, elevation of privilege, and in extreme cases, remote code execution. Mitigation This vulnerability is patched in json5 v2.2.2 and later. A patch has…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-9c47-m6qq-7p4h

  2. Revision 1 · created ·

    Published from osv record GHSA-9c47-m6qq-7p4h

Agent brief

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# Patch Next advisory brief: CVE-2022-46175

Advisory: Prototype Pollution in JSON5 via Parse Method
IDs: CVE-2022-46175, GHSA-9c47-m6qq-7p4h
Record: https://patchnext.com/advisories/cve-2022-46175 (revision 2, source checked 26 Oct 2026, 12:30 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: json5 2.2.2, 1.0.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm json5: affected >= 2.0.0, < 2.2.2; < 1.0.2; fixed in 1.0.2, 2.2.2

## Suggested inspection (read-only)
- `npm ls json5 --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 json5.
- 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-9c47-m6qq-7p4h (OSV record GHSA-9c47-m6qq-7p4h lists affected ranges: npm json5 >=2.0.0 =0 <1.0.2 (fixed))
- Verified: https://github.com/advisories/GHSA-9c47-m6qq-7p4h (GitHub-reviewed advisory GHSA-9c47-m6qq-7p4h lists affected ranges: npm json5 >=2.0.0 =0 <1.0.2)

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