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TI-2026-39517 Aliases CVE-2026-54696GHSA-x2f5-4prf-w687

Ruby JSON: JSON generator heap buffer overflow when streaming to an IO

Priority MEDIUM 51CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
Partial Red Hat: 1 fixed, 6 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

Ruby JSON is a JSON implementation for Ruby. Versions 2.9.0 through 2.19.8 are vulnerable to heap buffer overflow when the JSON generator is provided with an oversized streamed object. When streaming to an IO JSON.dump(obj, io) and JSON::State#generate(obj, io) can write past the internal JSON generator buffer when a streamed object contains an attacker-controlled string near 16 KB. Exploitation would result in a reliable process crash/denial of service. This issue has been fixed in version 2.19.9.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00412 35th percentileScored 2026-11-07
Fix Partial json (ruby): 2.19.9json (RubyGems): 2.19.9Red Hat: 2 advisoriesRed Hat: 1 fixed, 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
rubyjson2.9.0 to before 2.19.92.19.9Patch availableCNA
—json (RubyGems)2.9.0 to before 2.19.92.19.9Patch availableGHSA-x2f5-4prf-w687
  • json Vendorruby Affected 2.9.0 to before 2.19.9 Fixed in 2.19.9 Patch available CNA
  • json (RubyGems) Vendor— Affected 2.9.0 to before 2.19.9 Fixed in 2.19.9 Patch available GHSA-x2f5-4prf-w687

Remediation

  • Fix · CNA json (ruby) Fixed in 2.19.9
  • Fix · GHSA-x2f5-4prf-w687 json (RubyGems) Fixed in 2.19.9 Advisory →

Red Hat 2 advisories

  • RHSA-2026:48482 Released 2026-07-30 · Red Hat rating Low
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images ruby3.4-3.4.10-31.5.hum1@aarch64, ruby3.4-3.4.10-31.5.hum1@src, ruby3.4-3.4.10-31.5.hum1@x86_64 +10
  • RHSA-2026:47932 Released 2026-07-29 · Red Hat rating Low
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby4.0-4.0.6-37.1.hum1@aarch64, ruby4.0-4.0.6-37.1.hum1@src, ruby4.0-4.0.6-37.1.hum1@x86_64 +46

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat 3scale API Management Platform 2AffectedNo fix yet: Fix deferred
Red Hat AMQ ClientsAffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Dev SpacesAffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesFixed RHSA-2026:47932, RHSA-2026:48482
Not affected: 3 products
  • Red Hat Enterprise Linux AI (RHEL AI) 3
  • Red Hat Hardened Images
  • Red Hat OpenShift AI (RHOAI)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-54696
  2. 2026-10-03 Alias added: GHSA-x2f5-4prf-w687

References

Advisory 1

Other 5

  • TI-2026-71508 Integer overflow in GitLab allows code execution on the server KEVCVSS 3.1CRITICAL 10.0
  • TI-2026-50176 Use after free in ruby json CVSS 4.0HIGH 8.7
  • TI-2017-12709 Ruby before 2.4.3 allows Net::FTP command injection. CVSS 3.0HIGH 8.8
  • TI-2008-03501 Algorithmic complexity vulnerability in the WEBrick::HTTPUtils.split_header_value… CVSS 2.0HIGH 7.8
  • TI-2021-09891 In Ruby through 3.0 on Windows, a remote attacker can submit a crafted path when a Web… CVSS 3.1HIGH 7.5
  • TI-2025-18855 Net::IMAP vulnerable to possible DoS by memory exhaustion CVSS 3.1MEDIUM 6.5
See all 135 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences