dbcve.org
Integer OverflowWeakness · CWE-190

CVE-2026-54903

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.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. The 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 Ruby gem versions before 3.17.2 have an integer overflow in buf_append_string (buf.h:61) when parsing JSON strings exceeding 2 GB. The length converts to a negative size_t, causing memcpy to write out of bounds and corrupting heap memory, leading to denial of service.

MitigationUpgrade Oj gem to version 3.17.2 or later to patch the integer overflow vulnerability.

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. Check installed Oj gem version
    Run 'gem list oj' or execute 'ruby -roj -e "puts Oj::VERSION"' in your environment
    Affected if Version is lower than 3.17.2 (e.g., 3.17.1, 3.16.x, etc.)
  2. Identify if application parses untrusted JSON
    Review application code for Oj.parse() calls that process JSON from external sources such as API requests, file uploads, or user-provided input
    Affected if Oj parses JSON from untrusted or user-controlled sources
  3. Determine if large JSON strings can be processed
    Review application logic to see if it could receive or load JSON documents containing string values exceeding 2 GB in size
    Affected if The application could potentially process JSON strings larger than 2 GB from any source
  4. Check for heap corruption symptoms
    Monitor application logs and system crash reports for segmentation faults, memory corruption errors, or unexpected process termination during JSON parsing operations
    Affected if The application exhibits crashes or memory corruption specifically during parsing of large JSON payloads

You are affected if you are running an Oj gem version before 3.17.2 AND your application parses JSON from untrusted sources that could contain strings exceeding 2 GB in size.

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 Oj gem to version 3.17.2 or later to patch the integer overflow vulnerability.

Recommended fix High confidence

3.17.2

  1. Check the current version of the Oj gem installed in your project: `gem list oj` or check your Gemfile.lock
  2. Update the Oj gem to version 3.17.2 or later using Bundler: `bundle update oj` or manually update the version in your Gemfile to `gem 'oj', '~> 3.17'
  3. Run `bundle install` to install the updated gem
  4. Verify the installed version: `gem list oj` to confirm version 3.17.2 or higher is installed
  5. Restart any Ruby/Rails processes that are running to ensure they load the new gem version
  6. Test your application's JSON parsing functionality to ensure normal operation

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA2.0 h
8.0 hours of engineering $1,390
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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-2026-54903 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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