CVE-2026-54903 is a high-severity integer overflow or wraparound vulnerability in oj (rubygems), affecting versions < 3.17.2. It is fixed in 3.17.3.
Summary Oj.load is vulnerable to heap corruption when parsing a JSON string longer than 2 GB. An integer overflow in bufappendstring (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. Version Software: oj gem Affected: all versions with ext/oj/buf.h and ext/oj/parse.c Latest tested: 3.17.1 (confirmed present) Details ext/oj/buf.h, line 61: In parse.c, escape sequence handling computes the remaining string length as an int: ASAN report: Reproduce
An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value. Typical impact: incorrect size calculations leading to heap overflows or logic errors.
rubygems
oj (< 3.17.2)oj → 3.17.3 (rubygems)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
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Upgrade oj to 3.17.3 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-54903 is a high-severity integer overflow or wraparound vulnerability in oj (rubygems), affecting versions < 3.17.2. It is fixed in 3.17.3. An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value.
oj (rubygems) versions < 3.17.2 is affected.
Yes. CVE-2026-54903 is fixed in 3.17.3. Upgrade to this version or later.
Whether CVE-2026-54903 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade oj to 3.17.3 or later.