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CVE-2026-54592· NVD / CVE Program· CNA GitHub_M

Oj: Stack Buffer Overflow in Oj::Doc#each_child via Deeply Nested Input

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.27% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: ohler55 oj 3.17.3.

Low priority for now. Upgrade to ohler55 oj 3.17.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj::Doc#each_child, when invoked recursively over a deeply nested JSON document, overflows a fixed-size stack buffer and aborts the process, leading to DoS. In a two-step chain in ext/oj/fast.c, doc_each_child increments doc->where past the where_path[MAX_STACK = 100] array with no bounds check and never restores it (the doc->where-- is missing), so calling each_child recursively from inside the yield block drives doc->where beyond the array. On the next entry the function copies the path into the 800-byte stack-local buffer save_path[MAX_STACK] using wlen = doc->where - doc->where_path, so when the previous recursive call left doc->where past where_path[100] the wlen exceeds MAX_STACK and the memcpy overflows save_path on the C stack; because the Oj::Doc parser imposes no JSON nesting-depth limit (relying on a C-stack pressure check), deeply nested attacker input reaches this path. This issue has been fixed in version 3.17.3.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Jun 30, 2026
Updated
Jul 1, 2026
EPSS
0.2% · 18th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • ohler55 oj

    • < 3.17.3affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12ruby-ojbefore 3.14.2-1+deb12u13.14.2-1+deb12u1
Debian:13ruby-ojbefore 3.16.3-1+deb13u13.16.3-1+deb13u1
Debian:14ruby-ojbefore 3.17.3-13.17.3-1
RubyGemsojbefore 3.17.33.17.3

Same product

ohler55: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-54903Oj: Integer Overflow in Oj.load 2GB String Handling
    25Monitor
  • CVE-2026-54902Oj: Use-After-Free in Oj::Parser SAJ Long Key Callback
    25Monitor
  • CVE-2026-54901Oj: Use-After-Free in Oj::Parser array_class/hash_class GC Marking
    25Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-54500Jun 30, 2026 · Oj: intern.c form_attr has an uninitialized stack read
    21Monitor
  • ← EarlierCVE-2026-54502Jun 30, 2026 · Oj: Stack Buffer Overflow in Oj.dump via Large Indent
    25Monitor
  • Later →CVE-2026-54896Jun 30, 2026 · Oj: Heap Buffer Overflow in Oj.dump Exception Serialization via Large Indent
    8Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
ohler55 oj3.17.3 · descriptionVendor (CNA)
debian:ruby-oj3.14.2-1+deb12u1 · Debian:12Package registry (OSV)
debian:ruby-oj3.16.3-1+deb13u1 · Debian:13Package registry (OSV)
RubyGems:oj3.17.3Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-545000 days apartOj: intern.c form_attr has an uninitialized stack read
    21Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records