VulnerabilityDeferred

CVE-2026-54901

In versions prior to 3.17.2, Oj::Parser in usual mode does not mark array_class and hash_class references during garbage collection, leading to Use-After-Free.

MEDIUM 6.3EPSS 0.43%

Does this matter?

Lower severity and a low EPSS score (0.43%). Track it; it rarely justifies an emergency change on its own.

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj::Parser in usual mode does not mark array_class and hash_class references during garbage collection, leading to Use-After-Free. If GC runs after the class is assigned but before a parse, the class object is reclaimed, leaving the parser holding a dangling VALUE. The subsequent parse call dereferences the freed object, producing a segfault. This issue has been fixed in version 3.17.2.

CVSS 4.0: 6.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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/M
EPSS: 0.43% probability · 36th percentile
CISA KEV: Not listed
Weakness: CWE-416
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.