How severe is CVE-2026-33210?

No CVSS score has been assigned to CVE-2026-33210 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-33210?

CVE-2026-33210 affects the following packages: json (RubyGems), json (RubyGems), json (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2026-33210?

Update json to 2.19.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33210 is resolved across your whole dependency graph.

How do I detect CVE-2026-33210 in my RubyGems dependencies?

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.

How do I mitigate CVE-2026-33210 if there is no patch (or I can't update yet)?

Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Is CVE-2026-33210 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-33210 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-33210?

CVE-2026-33210 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-33210?

CVE-2026-33210 is classified as CWE-134 (CWE-134). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-33210 published, and has it been updated?

CVE-2026-33210 was published on March 20, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

Not in CISA KEV

CVE-2026-33210 — json

CVE-2026-33210 is a CWE-134 vulnerability in json. A fix is available for json — see the affected versions and patch details below.

Ruby JSON has a format string injection vulnerability

Also known asGHSA-3m6g-2423-7cp3

Published

Mar 20, 2026

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33210.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

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

Real-World Exposure

3 pkgs affected

💎json💎json💎json

Real-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

Impact

A format string injection vulnerability than that lead to denial of service attacks or information disclosure, when the allow_duplicate_key: false parsing option is used to parse user supplied documents.

This option isn't the default, if you didn't opt-in to use it, you are not impacted.

Patches

Patched in 2.19.2.

Workarounds

The issue can be avoided by not using the allow_duplicate_key: false parsing option.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`json`	≥ 2.18.0&&< 2.19.2	2.19.2`bundle update json --conservative`
💎RubyGems	`json`	≥ 2.16.0&&< 2.17.1.2	2.17.1.2`bundle update json --conservative`
💎RubyGems	`json`	≥ 2.14.0&&< 2.15.2.1	2.15.2.1`bundle update json --conservative`

Affected Products

1 product · 3 configurations

Application

jsonruby-lang

≥ 2.18.0 && < 2.19.2

range

Detection & mitigation playbook

Open-source dependency

Detect
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 2.19.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33210 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

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 HatImportant

A format string injection flaw was identified in Ruby JSON. This vulnerability allows a remote attacker to cause a denial of service or disclose sensitive information when processing specially crafted user-supplied documents with the `allow_duplicate_key: false` parsing option enabled. Red Hat Enterprise Linux 9.9…

Product	Fixed in	Advisory
Red Hat Enterprise Linux 10	`ruby4.0-0:4.0.3-34.el10_2`	RHSA-2026:20606
Red Hat Enterprise Linux 9	`ruby:4.0-9080020260513131334.9`	RHSA-2026:20596
Red Hat Hardened Images	`ruby4-0-main-0.3.2-37.2.hum1`	RHSA-2026:57565

Frequently Asked Questions

### Impact A format string injection vulnerability than that lead to denial of service attacks or information disclosure, when the `allow_duplicate_key: false` parsing option is used to parse user supplied documents. This option isn't the default, if you didn't opt-in to use it, you are not impacted. ### Patches Patched in `2.19.2`. ### Workarounds The issue can be avoided by not using the `allow_duplicate_key: false` parsing option.

O3 Security · Impact-Aware SCA

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