Stack-memory disclosure via wrong-buffer interning
Published Jun 30, 2026 · Updated Jun 30, 2026
Out-of-bounds read in Oj before 3.17.3 allows attackers to disclose process stack memory via JSON keys of at least 254 bytes. In ext/oj/intern.c, form_attr() fills heap buffer b for a long attribute name but passes uninitialized stack buffer buf to rb_intern3(), which reads len + 1 bytes. Exposure requires object mode and an application that parses attacker-controlled JSON and returns the resulting Symbol or EncodingError; leaked bytes are uncontrolled.
Summary
What happened
Out-of-bounds read in Oj before 3.17.3 allows attackers to disclose process stack memory via JSON keys of at least 254 bytes. In ext/oj/intern.c, form_attr() fills heap buffer b for a long attribute name but passes uninitialized stack buffer buf to rb_intern3(), which reads len + 1 bytes. Exposure requires object mode and an application that parses attacker-controlled JSON and returns the resulting Symbol or EncodingError; leaked bytes are uncontrolled.
The record
- CVE
- CVE-2026-54500
- Published
- Jun 30, 2026
- Updated
- Jun 30, 2026
- Vendor
- Peter Ohler
- Product
- Oj
- Classifications
- CWE-125, CWE-908
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 30, 2026CVE publishedPublication date reported by the CVE source.
- Jun 30, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.17.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- GHSA-fm7p-mprw-wjm9 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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