CVE-2026-54902Public exploitNetwork attack vector

Process crash via unprotected cached parser keys

Published Jun 30, 2026 · Updated Jul 1, 2026

Use-after-free in Oj before 3.17.2 allows remote attackers to crash a consuming process through crafted JSON parsed in SAJ mode. The parser retains a heap-backed Ruby String for object keys of at least 35 bytes without protecting it from garbage collection during the hash_end callback. If that callback triggers collection, C code later dereferences the reclaimed VALUE, causing a segmentation fault in the consuming 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

Use-after-free in Oj before 3.17.2 allows remote attackers to crash a consuming process through crafted JSON parsed in SAJ mode. The parser retains a heap-backed Ruby String for object keys of at least 35 bytes without protecting it from garbage collection during the hash_end callback. If that callback triggers collection, C code later dereferences the reclaimed VALUE, causing a segmentation fault in the consuming process.

The record

CVE
CVE-2026-54902
Published
Jun 30, 2026
Updated
Jul 1, 2026
Vendor
Peter Ohler
Product
Oj
Classifications
CWE-416, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

8.7GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
6.3GitHub CNACVSS: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-416Use After Free
T1499Endpoint Denial of Service

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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