Vulnerability in oj (CVE-2026-54502)
Summary
Vulnerability in oj (CVE-2026-54502). Risk of unauthorized operations or information disclosure. Exploitable via Oj.dump. Mitigation: upgrade to 3.17.3 or later.
Original description
The description as published by the source.
Summary
Oj.dump is vulnerable to a stack-based buffer overflow when a large :indent value is provided by the developer. fill_indent in dump.h calls memset(indent_str, ' ', (size_t)opts->indent) without validating the size. When opts->indent is set to INT_MAX (2,147,483,647), the (size_t) cast preserves the large value and memset writes 2 GB into the stack-allocated out buffer (4,184 bytes), corrupting the stack and crashing the process.
Version
- Software: oj gem
- Affected: all versions with
ext/oj/dump.h - Latest tested: 3.17.1 (confirmed present)
Details
ext/oj/dump.h, line 77:
static void fill_indent(Out out, int depth) {
if (0 < out->opts->indent) {
size_t len = (size_t)(out->opts->indent * depth);
// ...
memset(out->buf + ..., ' ', len); // len = 2147483647 * depth
The indent option is accepted as a plain Ruby integer and stored as int without range validation. Multiplying by depth can produce a value larger than any stack or heap buffer.
ASAN report:
==69820==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fd1fc201278
WRITE of size 2147483647 at 0x7fd1fc201278 thread T0
#0 memset
#1 fill_indent /ext/oj/dump.h:77
#2 dump_array /ext/oj/dump_compat.c:165
#3 oj_dump_obj_to_json_using_params /ext/oj/dump.c:818
#4 dump_body /ext/oj/oj.c:1429
#5 dump /ext/oj/oj.c:1480
Address is in stack of thread T0 at offset 4728 in fram…
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-2026-54502 has been found in oj.
Attackers can target a specific entry point like Oj.dump over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade oj to 3.17.3 or later.
If unsure, ask your IT team or search "oj CVE-2026-54502" on the vendor's site.
CVE-2026-54502 (oj) — CWE-121
Attack surface: Oj.dump / fill_indent / dump.h / INT_MAX
Patched: 3.17.3 — apply immediately
Workaround: The develop should not use extreme indents and should not offer the option for users to dump Ruby data with unlimited indentation size.
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.
A vulnerability (CWE-121) exists in oj. Attackers reach the vulnerable code path via Oj.dump.
Check the vendor advisory for the affected versions of oj. Attack surface: Oj.dump / fill_indent / dump.h / INT_MAX.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 3.17.3.
Workaround: The develop should not use extreme indents and should not offer the option for users to dump Ruby data with unlimited indentation size.
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 temporary workaround mitigate
The develop should not use extreme indents and should not offer the option for users to dump Ruby data with unlimited indentation size.パッチが適用されるまでの応急処置として、The develop should not use extreme indents and should not offer the option for users to dump Ruby data with unlimited indentation size. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply 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。
-
4Post-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-2026-54502 ruby-oj Fixed in: 3.14.2-1+deb12u1
- Ubuntu UBUNTU-CVE-2026-54502 ruby-oj
References
- package github.com
- web github.com
- web github.com