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Not in CISA KEV
HIGH severity

jsondiffpatch patch APIs are vulnerable to prototype pollutionGHSA-j4fx-xxwh-2485

HIGHFix: benjamine/jsondiffpatch@381c012

GHSA-j4fx-xxwh-2485 is a high-severity (CVSS 8.2) CWE-1321 vulnerability in jsondiffpatch. A fix is available for jsondiffpatch — see the affected versions and patch details below.

Also known asCVE-2026-8657
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for GHSA-j4fx-xxwh-2485.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs32th percentile — riskier than 32% of all scored CVEsHighest risk
0.00%0.39%0.78%1.17%0.1%0.4%Jun 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

608other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
jsondiffpatchnpm
3.2Mdownloads / week

Description

Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmjsondiffpatchall versions0.7.6npm install jsondiffpatch@0.7.6

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jsondiffpatch, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update jsondiffpatch to 0.7.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-j4fx-xxwh-2485 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like __proto__ or constructor.prototype, allowing modification of Object.prototype.
O3 Security · Impact-Aware SCA

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