CVE-2026-54903: Oj: Integer Overflow in Oj.load 2GB String Handling

June 19, 2026

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.

References

github.com/advisories/GHSA-475m-ph3x-64gp
github.com/ohler55/oj/security/advisories/GHSA-475m-ph3x-64gp
nvd.nist.gov/vuln/detail/CVE-2026-54903

Code Behaviors & Features

Detect and mitigate CVE-2026-54903 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →