CVE-2026-54900Public exploitNetwork attack vector

Process crash via truncated JSON key length

Published Jun 30, 2026 · Updated Jun 30, 2026

Heap corruption in Oj before 3.17.2 allows remote attackers to crash a Ruby process via a crafted JSON object key. In usual mode with create_id enabled, form_attr truncates a 65,535-byte key length to -1 and passes it to memcpy as SIZE_MAX. The consuming application must pass attacker-controlled JSON to Oj::Parser#parse with that mode and option enabled; exploitation corrupts heap memory and interrupts the process.

CVSS severity6.3
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap corruption in Oj before 3.17.2 allows remote attackers to crash a Ruby process via a crafted JSON object key. In usual mode with create_id enabled, form_attr truncates a 65,535-byte key length to -1 and passes it to memcpy as SIZE_MAX. The consuming application must pass attacker-controlled JSON to Oj::Parser#parse with that mode and option enabled; exploitation corrupts heap memory and interrupts the process.

The record

CVE
CVE-2026-54900
Published
Jun 30, 2026
Updated
Jun 30, 2026
Vendor
Peter Ohler
Product
Oj
Classifications
CWE-787, CWE-190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 30, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=< 3.17.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Peter Ohler · Ojversion=< 3.17.2

Published CVSS scores

6.3GitHub, Inc.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

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-190Integer Overflow or Wraparound
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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