CVE-2026-54903

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj.load is vulnerable to heap corruption when parsing a JSON string longer than 2 GB. An integer overflow in buf_append_string (buf.h:61) converts the string length to a large negative size_t, causing memcpy to copy an astronomically large amount of data out of bounds. This crashes the process and can corrupt adjacent heap memory. The issue has been fixed in version 3.17.2.

CVSS 4.0

6.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 26% of CVEs (scores of 2026-10-25)

CWE

CWE-190

Published

2026-07-01

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Packages (OSV)

References

• https://github.com/ohler55/oj/security/advisories/GHSA-475m-ph3x-64gp
• https://github.com/ohler55/oj/security/advisories/GHSA-475m-ph3x-64gp

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