ruby json up to 2.19.8 JSON::State#generate heap-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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4.6$0-$5k1.99-

Summaryinfo

A vulnerability classified as critical was found in ruby json up to 2.19.8. Affected is the function JSON::State#generate. The manipulation results in heap-based overflow. This vulnerability is identified as CVE-2026-54696. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in ruby json up to 2.19.8. It has been classified as critical. Affected is the function JSON::State#generate. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-54696 since 06/16/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available.

Upgrading to version 2.19.9 eliminates this vulnerability. The upgrade is hosted for download at github.com.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.7
VulDB Meta Temp Score: 4.6

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 3.7
CNA Vector (GitHub_M): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: json 2.19.9

Timelineinfo

06/16/2026 CVE reserved
07/01/2026 +15 days Advisory disclosed
07/01/2026 +0 days VulDB entry created
07/01/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-x2f5-4prf-w687
Status: Confirmed

CVE: CVE-2026-54696 (🔒)
GCVE (CVE): GCVE-0-2026-54696
GCVE (VulDB): GCVE-100-375396

Entryinfo

Created: 07/01/2026 10:04
Changes: 07/01/2026 10:04 (67)
Complete: 🔍
Cache ID: 216::103

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