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TI-2026-39669 Aliases CVE-2026-54897GHSA-9ppp-w3g4-fh4q

Oj : Use-After-Free in Oj::Doc Iterators via Reentrant Close

Priority MEDIUM 44CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to 3.17.2, Oj::Doc iterators (each_value, each_child, each_leaf) were vulnerable to a heap use-after-free. When a Ruby block yielded during iteration calls doc.close or d.close, the document's heap memory is freed while the C iterator is still running. When control returns from the block, the iterator reads from the freed region, producing a use-after-free accessible from pure Ruby. This issue has been fixed in version 3.17.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00203 10th percentileScored 2026-11-07
Fix Fixed oj (ohler55): 3.17.2oj (RubyGems): 3.17.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ohler55ojbefore 3.17.23.17.2Patch availableCNA
—oj (RubyGems)before 3.17.33.17.3Patch availableGHSA-9ppp-w3g4-fh4q
  • oj Vendorohler55 Affected before 3.17.2 Fixed in 3.17.2 Patch available CNA
  • oj (RubyGems) Vendor— Affected before 3.17.3 Fixed in 3.17.3 Patch available GHSA-9ppp-w3g4-fh4q

Remediation

  • Fix · CNA oj (ohler55) Fixed in 3.17.2
  • Fix · GHSA-9ppp-w3g4-fh4q oj (RubyGems) Fixed in 3.17.3 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-54897
  2. 2026-10-03 Alias added: GHSA-9ppp-w3g4-fh4q
  3. 2026-10-07 Affected versions changed · GHSA-9ppp-w3g4-fh4q
  4. 2026-10-07 3 new references · GHSA-9ppp-w3g4-fh4q

References

Advisory 1

Other 4

  • TI-2026-39426 Oj: Stack Buffer Overflow in Oj::Doc#each_child via Deeply Nested Input CVSS 3.1HIGH 7.5
  • TI-2026-39672 Oj: Negative-Size memcpy in Oj::Parser create_id Attribute Handling CVSS 4.0MEDIUM 6.3
  • TI-2026-39348 Oj: Stack Buffer Overflow in Oj.dump via Large Indent CVSS 4.0MEDIUM 6.3
  • TI-2026-39675 Oj: Integer Overflow in Oj.load 2GB String Handling CVSS 4.0MEDIUM 6.3
  • TI-2026-39674 Oj: Use-After-Free in Oj::Parser SAJ Long Key Callback CVSS 4.0MEDIUM 6.3
  • TI-2026-39673 Oj: Use-After-Free in Oj::Parser array_class/hash_class GC Marking CVSS 4.0MEDIUM 6.3
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences