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CVE-2026-54696

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

Published: Jun 30, 2026Updated: Jul 2, 2026 Sources: CVE List NVDCWE-122
3.7LOW
NVD MITRE
EPSS Score
0.3%
Top 77.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
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Weaknesses

CWE-122CWE-131CWE-787

Affected Products

ruby
oss-project·JP
jsonLibrary
OSS Libraries / rubygems

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://github.com/ruby/json/releases/tag/v2.19.9
github.com
https://github.com/ruby/json/security/advisories/GHSA-x2f5-4prf-w687
github.com

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