How severe is CVE-2026-54502?

CVE-2026-54502 has a CVSS 4.0 base score of 6.3, rated medium severity.

Is CVE-2026-54502 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-54502?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-54502 published?

CVE-2026-54502 was published on 2026-07-01.

CVE-2026-54502

CVE-2026-54502 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-121.

Key facts

Severity: Medium (CVSS 4.0 base score 6.3)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-121
Published: 2026-07-01
Last modified: 2026-07-01

Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj.dump is vulnerable to a stack-based buffer overflow when a large :indent value is provided by the developer. fill_indent in dump.h calls memset(indent_str, ' ', (size_t)opts->indent) without validating the size. When opts->indent is set to INT_MAX (2,147,483,647), the (size_t) cast preserves the large value and memset writes 2 GB into the stack-allocated out buffer (4,184 bytes), corrupting the stack and crashing the process. This issue has been fixed in version 3.17.2.

Frequently asked questions

What is CVE-2026-54502?: Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj.dump is vulnerable to a stack-based buffer overflow when a large :indent value is provided by the developer. fill_indent in dump.h calls memset(indent_str, ' ', (size_t)opts->indent) without validating the size. When opts->indent is set to INT_MAX (2,147,483,647), the (size_t) cast preserves the large value and memset writes 2 GB into the stack-allocated out buffer (4,184 bytes), corrupting the stack and crashing the process. This issue has been fixed in version 3.17.2.
How severe is CVE-2026-54502?: CVE-2026-54502 has a CVSS 4.0 base score of 6.3, rated medium severity.
Is CVE-2026-54502 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-54502?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-54502 published?: CVE-2026-54502 was published on 2026-07-01.

References

https://github.com/ohler55/oj/security/advisories/GHSA-3v45-f3vh-wg7m

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