Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
📦
📦 npm
Not in CISA KEV
CRITICAL severity

CVE-2020-7770 — json8

CRITICALFix: sonnyp/JSON8@2e89026

CVE-2020-7770 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in json8. 1 public exploit reference exists, so weaponization risk is real. A fix is available for json8 — see the affected versions and patch details below.

Prototype pollution in json8

Also known asGHSA-7h43-gx24-p529SNYK-JS-JSON8-1017116
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs79th percentile — riskier than 79% of all scored CVEsHighest risk
0.00%0.80%1.60%2.39%0.3%1.9%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2020-7770 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

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.

7other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
json8npm
10Kdownloads / week

Description

This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmjson8all versions1.0.3npm install json8@1.0.3

Affected Products

1 product · 1 configurations
Application
json8json8_project
< 1.0.3
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

This affects the package json8 before 1.0.3. The function adds in the ta…

snyk.ioNVDDec 2022

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for json8, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update json8 to 1.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-7770 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

This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
O3 Security · Impact-Aware SCA

Is CVE-2020-7770 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2020-7770: json8 — Fixed in 1.0.3