CVE-2026-54902 | Oj (Optimized JSON) is a JSON parser and Object marshaller p… | CVSS 6.3 MEDIUM

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, is vulnerable to Use-After-Free when in SAJ mode. The Oj::Parser does not protect cached object keys (≥ 35 bytes) from garbage collection, and a Ruby callback that triggers GC inside hash_end can cause the key string to be reclaimed while the C parser still holds a pointer to it. The subsequent access to the freed string VALUE results in a segfault, confirmed by an RIP pointing to address 0x4242 (a canary-style pattern suggesting control over the freed memory's content). This issue has been fixed in version 3.17.2.

Metadata

CVE ID: CVE-2026-54902
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-06-16 13:49 UTC
Published: 2026-06-30 23:40 UTC
Last updated: 2026-06-30 23:40 UTC
Primary CWE: CWE-416
CWE-416: Use After Free
Vendor / Product: ohler55 / oj
Sources: cve.org · NVD

Severity & Metrics

6.3 MEDIUM CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Affected products (1)

Vendor	Product	Platform	Versions
ohler55	oj	—	< 3.17.2

Weakness (CWE)

CWE	Source	Description
CWE-416	cna	CWE-416: Use After Free

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.3	MEDIUM	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References (1)

https://github.com/ohler55/oj/security/advisories/GHSA-m578-w5vf-rfcm https://github.com/ohler55/oj/security/advisories/GHSA-m578-w5vf-rfcm