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VulnerabilityPublished

CVE-2026-54903: ohler55 oj · Integer Overflow or Wraparound

Affects ohler55 ojSource CVE Database V5

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Not known to be exploited · CVSS 6.3 Medium : upgrade to 3.17.2 when convenient.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 4.0 base score
6.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.17.2
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 30 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Upgrade ohler55 oj to 3.17.2.

Affected software

ProductAffectedFixed in
ohler55ojAffected
  • <3.17.2
Fixed in
  • 3.17.2
RubyGemsojpkg:gem/ojOther threatsAffected
  • <3.17.2
Fixed in
  • 3.17.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Oj to version 3.17.2 or later, where this integer overflow and heap corruption issue has been fixed. Patch status is confirmed by the vendor's versioning information. No other mitigations are indicated.

Description

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.

References

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