What is CVE-2026-33210?

CVE-2026-33210 is a critical-severity vulnerability in Ruby Json, classified under Use of Externally-Controlled Format String. CVSS score: 9.1/10. Published 2026-03-20.

How severe is CVE-2026-33210?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Ruby Json

CVE-2026-33210

Ruby JSON is a JSON implementation for Ruby. From version 2.14.0 to before versions 2.15.2.1, 2.17.1.2, and 2.19.2, a format string injection vulnerability can lead to denial of service attacks or information disclosure, when the allow_dup…

EPSS: 0.008 (54.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

Affected products

Ruby Json — versions >= 2.14.0, < 2.15.2.1, >= 2.16.0, < 2.17.1.2, >= 2.18.0, < 2.19.2
Ruby-lang Json

Weakness classification (CWE)

CWE-134 — Use of Externally-Controlled Format String

References

security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
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Frequently asked questions

What is CVE-2026-33210?: CVE-2026-33210 is a critical-severity vulnerability in Ruby Json, classified under Use of Externally-Controlled Format String. CVSS score: 9.1/10. Published 2026-03-20.
How severe is CVE-2026-33210?: Critical severity. CVSS v3 base score is 9.1 out of 10.