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

Q: How do I fix CVE-2020-10663?

json: upgrade to newer than 2.2.0; fedora: mitigate or apply the listed mitigation; leap: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-10663 being exploited?

CVE-2020-10663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-10663 affect?

CVE-2020-10663 affects json, fedora, leap. Severity is high (CVSS 7.5). 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-collect

Q: How urgent is CVE-2020-10663?

Priority 60/100. High severity; EPSS top 6%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

This week

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2020-10663 is a high-severity flaw (CVSS 7.5) affecting json, fedora, leap. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
EPSS top 6%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	6.8% (top 6%)
CISA exploited list	No
Weakness	CWE-20
Published	2020-04-28
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: apple · debian · fedoraproject · json project · opensuse

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-04-28 21:15 UTCPublished CVE record published
2026-06-17 02:48 UTCUpdated Record last modified

json project json UPGRADE

Affected: <= 2.2.0

Fixed in: newer than 2.2.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy json || rpm -q json || json --version

2. UPGRADE to newer than 2.2.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade json

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade json

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

fedoraproject fedora MITIGATE

Affected: 30 · 31

Fixed in: no fixed release known

Safe to downgrade to: a release before 30

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse leap MITIGATE

Affected: 15.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 15.1

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 8.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple macos MITIGATE

Affected: 11.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0.1

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-10663?

json: upgrade to newer than 2.2.0; fedora: mitigate or apply the listed mitigation; leap: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-10663 being exploited?

CVE-2020-10663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-10663 affect?

CVE-2020-10663 affects json, fedora, leap. Severity is high (CVSS 7.5). 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-collect

How urgent is CVE-2020-10663?

Priority 60/100. High severity; EPSS top 6%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities · macOS vulnerabilities · Ruby vulnerabilities

Related CVEs

CVE-2020-7712 HIGH 7.2 UPGRADE DOWNGRADE This affects the package json before 10.0.0
CVE-2026-33210 CRITICAL 9.1 UPGRADE Ruby JSON is a JSON implementation for Ruby

References

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