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Stack-based Buffer OverflowWeakness · CWE-121

CVE-2026-54502

MEDIUM · 6.3 CVSS v4.0 Published 2026-07-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click 7 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Oj gem versions before 3.17.2 have a stack-based buffer overflow in the dump functionality. When a large :indent value (like INT_MAX) is passed to Oj.dump, the fill_indent function in dump.h calls memset with the unsanitized value, causing a write of ~2GB into a 4,184-byte stack buffer, corrupting the stack and crashing the process.

MitigationUpgrade to Oj version 3.17.2 or later which includes bounds checking on the indent parameter. Avoid passing unvalidated user input directly to the :indent option as a defensive measure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Oj gem is installed
    Run `gem list oj` or check your Gemfile/Gemfile.lock for the oj gem dependency
    Affected if The Oj gem is present in the Ruby environment
  2. Identify installed Oj version
    Run `gem list oj` to see the installed version, or run `ruby -e "require 'oj'; puts Oj::VERSION"`
    Affected if The version is lower than 3.17.2 (e.g., 3.17.0, 3.16.0, etc.)
  3. Check for Oj.dump usage with :indent option
    Search codebases for patterns like `Oj.dump(..., indent:` or `Oj.generate(..., indent:` to see if the :indent parameter is used
    Affected if Code calls Oj.dump or Oj.generate with an :indent argument
  4. Determine if :indent receives external input
    Review code that passes the :indent value; check if it comes from user input, config files, API parameters, or environment variables without validation
    Affected if The :indent value is derived from untrusted or unvalidated sources rather than hardcoded small integers
  5. Verify indent value validation exists
    Search for any bounds checking on the indent parameter before passing to Oj.dump (e.g., looking for `indent.to_i < X` or similar validation logic)
    Affected if No validation exists to prevent large integer values (like INT_MAX) from reaching Oj.dump

A user is affected if Oj gem version is below 3.17.2 AND the application uses Oj.dump with an :indent parameter that can accept large or unvalidated integer values.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Oj version 3.17.2 or later which includes bounds checking on the indent parameter. Avoid passing unvalidated user input directly to the :indent option as a defensive measure.

Recommended fix High confidence

Oj gem version 3.17.2 or later

  1. Check the current version of the Oj gem in your project by running: gem list oj
  2. Upgrade the Oj gem to version 3.17.2 or later using: gem install oj -v '>= 3.17.2' or add to Gemfile: gem 'oj', '>= 3.17.2'
  3. Run bundle update oj to update dependencies
  4. Verify the upgraded version: gem list oj
  5. Run your application's test suite to ensure functionality is intact

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,190
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-54502 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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