GHSA-3m6q-jj5j-38c9

Suggest an improvement
Source
https://github.com/advisories/GHSA-3m6q-jj5j-38c9
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-3m6q-jj5j-38c9/GHSA-3m6q-jj5j-38c9.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-3m6q-jj5j-38c9
Aliases
  • CVE-2026-54592
Published
2026-06-19T19:36:28Z
Modified
2026-06-19T19:45:55.210194599Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
Oj: Stack Buffer Overflow in Oj::Doc#each_child via Deeply Nested Input
Details

Summary

Oj::Doc#each_child, when invoked recursively over a deeply nested JSON document, overflows a fixed-size stack buffer and aborts the process. This is a denial of service reachable from untrusted JSON.

Details

Two-step chain in ext/oj/fast.c:

  1. doc_each_child (~line 1501) increments doc->where past the where_path[MAX_STACK = 100] array with no bounds check, and never restores it (doc->where-- is missing). Calling each_child recursively from inside the yield block therefore drives doc->where beyond the array.

  2. On the next entry (~line 1478) the function copies the path into a stack-local buffer:

    Leaf  save_path[MAX_STACK];           // 800-byte stack buffer
size_t wlen = doc->where - doc->where_path;
if (0 < wlen) {
    memcpy(save_path, doc->where_path, sizeof(Leaf) * (wlen + 1));
}

    When the previous recursive call left doc->where past where_path[100], wlen exceeds MAX_STACK and the memcpy overflows save_path on the C stack.

The Oj::Doc parser imposes no JSON nesting-depth limit (it relies on a C-stack pressure check), so deeply nested attacker input reaches this path.

Proof of Concept

require 'oj'
depth = 200
payload = '[' * depth + '1' + ']' * depth
Oj::Doc.open(payload) do |doc|
  r = lambda { doc.each_child { |_| r.call } }
  r.call
end

Recursion depth <= 99 iterates normally; depth >= 101 aborts. lldb backtrace on the affected build (ruby 3.3.8 / arm64-darwin24):

SIGABRT
#2 __abort
#3 __stack_chk_fail
#4 doc_each_child   (oj.bundle, fast.c)

Impact

Reliable denial of service: any endpoint that calls Oj::Doc.open(untrusted) { |d| d.each_child ... } recursively can be crashed with a small deeply-nested payload. On builds with a stack protector (the default, -fstack-protector-strong) the canary aborts the process before the saved return address is used. The Step-1 heap OOB writes into struct _doc fields do occur, but are masked in practice because the Step-2 stack overflow crashes first; turning them into anything beyond a crash has not been demonstrated.

Patches

Fixed in 3.17.3: doc_each_child now bounds-checks before incrementing doc->where (raising Oj::DepthError) and restores doc->where after the loop, matching the existing each_leaf pattern. Verified on the fixed build: depth >= 101 raises a clean Oj::DepthError instead of aborting.

Credit

Reported by Zac Wang (@7a6163).

Database specific 
{
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T19:36:28Z",
    "nvd_published_at": null,
    "severity": "HIGH",
    "cwe_ids": [
        "CWE-125",
        "CWE-787"
    ]
}
References

Affected packages

RubyGems / oj

Package

Name
oj
Purl
pkg:gem/oj

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
3.17.3

Affected versions

0.*
0.5
0.5.1
0.5.2
0.6.0
0.7.0
0.8.0
0.9.0
1.*
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.0.5
1.0.6
1.1.0
1.1.1
1.2.0
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.2.7
1.2.8
1.2.9
1.2.10
1.2.11
1.2.12
1.2.13
1.3.0
1.3.2
1.3.4
1.3.5
1.3.6
1.3.7
1.4.0
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6a2
1.4.6
1.4.7
2.*
2.0.0
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
2.0.6
2.0.7
2.0.8
2.0.9
2.0.10
2.0.11
2.0.12
2.0.13
2.0.14
2.1.0
2.1.1
2.1.2
2.1.3
2.1.4
2.1.6
2.1.7
2.2.0
2.2.1
2.2.2
2.2.3
2.3.0
2.4.0
2.4.1
2.4.2
2.4.3
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.6.0
2.6.1
2.7.0
2.7.1
2.7.2
2.7.3
2.8.0
2.8.1
2.9.0
2.9.1
2.9.2
2.9.3
2.9.4
2.9.5
2.9.6
2.9.7
2.9.8
2.9.9
2.10.0
2.10.1
2.10.2
2.10.3
2.10.4
2.11.0
2.11.1
2.11.2
2.11.3
2.11.4
2.11.5
2.12.0
2.12.1
2.12.2
2.12.3
2.12.4
2.12.5
2.12.6
2.12.7
2.12.8
2.12.9
2.12.10
2.12.11
2.12.12
2.12.13
2.12.14
2.13.0
2.13.1
2.14.0
2.14.1
2.14.2
2.14.3
2.14.4
2.14.5
2.14.6
2.15.0
2.15.1
2.16.0
2.16.1
2.17.0
2.17.1
2.17.2
2.17.3
2.17.4
2.17.5
2.18.0
2.18.1
2.18.2
2.18.3
2.18.4
2.18.5
3.*
3.0.0
3.0.1
3.0.2
3.0.3
3.0.4
3.0.5
3.0.6
3.0.7
3.0.8
3.0.9
3.0.10
3.0.11
3.1.0
3.1.2
3.1.3
3.1.4
3.2.0
3.2.1
3.3.0
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.3.6
3.3.7
3.3.8
3.3.9
3.3.10
3.4.0
3.5.0
3.5.1
3.6.0
3.6.2
3.6.3
3.6.4
3.6.5
3.6.6
3.6.7
3.6.8
3.6.9
3.6.10
3.6.11
3.6.12
3.6.13
3.7.0
3.7.1
3.7.2
3.7.3
3.7.4
3.7.5
3.7.6
3.7.7
3.7.8
3.7.9
3.7.10
3.7.11
3.7.12
3.8.0
3.8.1
3.9.0
3.9.1
3.9.2
3.10.0
3.10.1
3.10.2
3.10.3
3.10.5
3.10.6
3.10.7
3.10.8
3.10.9
3.10.10
3.10.11
3.10.12
3.10.13
3.10.14
3.10.15
3.10.16
3.10.17
3.10.18
3.11.0
3.11.1
3.11.2
3.11.3
3.11.4
3.11.5
3.11.6
3.11.7
3.11.8
3.12.0
3.12.1
3.12.2
3.12.3
3.13.0
3.13.1
3.13.2
3.13.3
3.13.4
3.13.5
3.13.6
3.13.7
3.13.8
3.13.9
3.13.10
3.13.11
3.13.12
3.13.13
3.13.14
3.13.15
3.13.16
3.13.17
3.13.18
3.13.19
3.13.20
3.13.21
3.13.22
3.13.23
3.14.0
3.14.1
3.14.2
3.14.3
3.15.0
3.15.1
3.16.0
3.16.1
3.16.2
3.16.3
3.16.4
3.16.5
3.16.6
3.16.7
3.16.8
3.16.9
3.16.10
3.16.11
3.16.12
3.16.13
3.16.14
3.16.15
3.16.16
3.16.17
3.17.0
3.17.1

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-3m6q-jj5j-38c9/GHSA-3m6q-jj5j-38c9.json"