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Public proof of concept

CVE-2020-10663

A public proof of concept exists; no exploitation attested.

  • Published2020-04-28
  • WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2020-04-2821:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-10663?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-10663?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Debian debian linux
BranchAffectedFixed in
8.0= 8.0no fix published
10.0= 10.0no fix published
Fedoraproject fedora
BranchAffectedFixed in
30.x= 30no fix published
31.x= 31no fix published
Apple macos
BranchAffectedFixed in
11.0= 11.0.1no fix published

3 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • rubygem-abrtAlmaLinux:8all versions · fixed in 0.3.0-4.module_el8.5.0+259+8cec6917and 1 other package
  • rubygem-abrtAlmaLinux:8all versions · fixed in 0.3.0-4.module_el8.5.0+2623+08a8ba32and 1 other package
  • rubygem-abrtAlmaLinux:8all versions · fixed in 0.3.0-4.module_el8.5.0+2625+ec418553and 1 other package
  • rubygem-bsonAlmaLinux:8all versions · fixed in 4.3.0-2.module_el8.5.0+259+8cec6917and 1 other package
  • rubygem-bsonAlmaLinux:8all versions · fixed in 4.3.0-2.module_el8.5.0+2625+ec418553and 1 other package
  • rubygem-bsonAlmaLinux:8all versions · fixed in 4.5.0-1.module_el8.5.0+250+ba22dbf7and 1 other package
  • rubygem-bsonAlmaLinux:8all versions · fixed in 4.5.0-1.module_el8.5.0+2623+08a8ba32and 1 other package
  • rubygem-mongoAlmaLinux:8all versions · fixed in 2.5.1-2.module_el8.5.0+259+8cec6917and 1 other package

11 more package ranges on OSV.dev

Full record on NVD

Fix

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedrails-lts/json_cve_2020_10663
PoC-in-GitHub

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-20read 2026-10-23
  • FIRST EPSSEPSS score6.8 %2026-10-22
  • PoC-in-GitHubproof of concept1read 2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2020-04-28
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-10663?

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.

Is CVE-2020-10663 actively exploited?

Active exploitation of CVE-2020-10663 has not been confirmed. Its EPSS score was 6.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-10663?

CVE-2020-10663 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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