CVE-2026-33210: Ruby JSON has a format string injection vulnerability
Vulnerability summary
CVE-2026-33210 is a critical (CVSS 9.1) vulnerability in ruby-lang json. EPSS estimates a 0.87% chance of exploitation in the next 30 days, higher than 58.9% of scored vulnerabilities.
Severe, CVSS 8.3 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 1Timeline
- 20-03-2026PublishedVulnerability first disclosed.
- 21-08-2026Last modifiedVulnerability information updated.
Description
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_duplicate_key: false parsing option is used to parse user supplied documents. This issue has been patched in versions 2.15.2.1, 2.17.1.2, and 2.19.2.
CVSS metrics
10 scores · 7 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · WolfiEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · RubygemsEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- NVDNIST8.3HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · UbuntuEcosystem advisory · calculated9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- OSV · DebianEcosystem advisory · calculated9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- NVDNIST9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS trend
Probability
0.87%
Chance of exploitation in the next 30 days
Percentile
59%
Versus all other CVEs
30-day change
Decrease -0.14 pp
From 1.01% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard22 products
- cinc-auditor< 7.0.107-r1
- gitlab-exporter-18.9< 18.9.2-r1
- jruby-10.1All versions (No fix recorded)
- logstash-9.2< 9.2.7-r1
- logstash-9.2-iamguarded-compat< 9.2.7-r1
Wolfi14 products
- cinc-auditor< 7.0.107-r1
- jruby-10.1All versions (No fix recorded)
- logstash-9.3< 9.3.2-r1
- logstash-9.3-iamguarded-compat< 9.3.2-r1
- logstash-9.3-with-output-opensearch< 9.3.2-r1
Debian1 product
- ruby-json< 2.19.2+dfsg-1
Ruby1 product
- json≥ 2.14.0, < 2.15.2.1 | ≥ 2.16.0, < 2.17.1.2 | ≥ 2.18.0, < 2.19.2
Ruby-lang1 product
- json≥ 2.14.0, < 2.15.2.1 | ≥ 2.16.0, < 2.17.1.2 | ≥ 2.18.0, < 2.19.2
RubyGems1 product
- json≥ 2.18.0, < 2.19.2 | ≥ 2.16.0, < 2.17.1.2 | ≥ 2.14.0, < 2.15.2.1
Ubuntu1 product
- ruby-jsonAll versions (No fix recorded)
7 vendors · 41 products
References
14 links- github.com/ruby/json/security/advisories/GHSA-3m6g-2423-7cp3X Refsource CONFIRMREPORTAdvisoryWEBMitigationVendor Advisory
