Out-of-Bounds Read in oj (CVE-2026-54592)
Summary
Vulnerability in oj (CVE-2026-54592). Risk of unauthorized operations or information disclosure. Exploitable via doc_each_child. Mitigation: upgrade to 3.17.3 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54592 has been found in oj.
Attackers can target a specific entry point like doc_each_child over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade oj to 3.17.3 or later.
If unsure, ask your IT team or search "oj CVE-2026-54592" on the vendor's site.
CVE-2026-54592 (oj) — CWE-125 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: doc_each_child / each_child / wlen / MAX_STACK
Patched: 3.17.3 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in oj. Attackers reach the vulnerable code path via doc_each_child without authentication.
Check the vendor advisory for the affected versions of oj. Attack surface: doc_each_child / each_child / wlen / MAX_STACK.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 3.17.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'oj' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'oj' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
ojを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade oj to 3.17.3ステージング環境で 3.17.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-54592 ruby-oj Fixed in: 3.14.2-1+deb12u1
- Ubuntu UBUNTU-CVE-2026-54592 ruby-oj
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- web github.com