CVE-2020-10663 — json
HIGHCVE-2020-10663 is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in json. 2 public exploit references exist, so weaponization risk is real. A fix is available for json — see the affected versions and patch details below.
Unsafe object creation in json RubyGem
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2020-10663 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
jsonReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
The JSON gem through 2.2.0 for Ruby, as used in Ruby 2.4 through 2.4.9, 2.5 through 2.5.7, and 2.6 through 2.6.5, has an Unsafe Object Creation Vulnerability. This is quite similar to CVE-2013-0269, but does not rely on poor garbage-collection behavior within Ruby. Specifically, use of JSON parsing methods can lead to creation of a malicious object within the interpreter, with adverse effects that are application-dependent.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | json | all versions | 2.3.0bundle update json --conservative |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for json, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update json to 2.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-10663 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-10663 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2020-10663. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat CloudForms 5 uses vulnerable rubygem-json, however, is not vulnerable in Ruby since it does not use version which includes JSON into stdlib. This issue affects the version of JSON(embedded in pcs) as shipped with Red Hat Gluster Storage 3. However, the vulnerable method calls are currently not used by the…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | ruby:2.5-8040020200923213910.522a0ee4 | RHSA-2021:2587 |
| Red Hat Enterprise Linux 8 | ruby:2.6-8040020210430142949.522a0ee4 | RHSA-2021:2588 |
| Red Hat Enterprise Linux 8 | pcs-0:0.10.4-6.el8_2.1 | RHSA-2020:2462 |
| Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions | pcs-0:0.10.1-4.el8_0.5 | RHSA-2020:2473 |
| Red Hat Enterprise Linux 8.1 Extended Update Support | pcs-0:0.10.2-4.el8_1.1 | RHSA-2020:2670 |
| Red Hat Enterprise Linux 8.1 Update Services for SAP Solutions | ruby:2.6-8010020220201152941.c27ad7f8 | RHSA-2022:0581 |
| Red Hat Enterprise Linux 8.2 Extended Update Support | ruby:2.6-8020020220201131207.4cda2c84 | RHSA-2022:0582 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-ruby25-ruby-0:2.5.9-9.el7 | RHSA-2021:2104 |
Frequently Asked Questions
Is CVE-2020-10663 in your dependencies?
O3 Security finds CVE-2020-10663 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.