GHSA-w7fw-mjwx-w883 · 深刻度： low · エコシステム： npm — qs's arrayLimit bypass in comma parsing allows denial of service
### Summary The `arrayLimit` option in qs does not enforce limits for comma-separated values when `comma: true` is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284). ### Details When the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `['a', 'b', 'c']`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation. **Vulnerable code** (lib/parse.js: lines ~40-50): ```js if (val && typeof val === 'string' && options.comma && val.indexOf(',') > -1) { return val.split(','); } if (options.throwOnLimitExceeded && currentArrayLength >= options.arrayLimit) { throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + ' element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.'); } return val; ``` The `split(',')` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p). ### PoC **Test 1 - Basic bypass:** ``` npm install qs ``` ```js const qs = require('qs'); const payload = 'a=' + ','.repeat(25); // 26 elements after split (bypasses arrayLimit: 5) const options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true }; try { const result = qs.parse(payload, options); console.log(result.a.length); // Outputs: 26 (bypass successful) } catch (e) { console.log('Limit enforced:', e.message); // Not thrown } ``` **Configuration:** - `comma: true` - `arrayLimit: 5` - `throwOnLimitExceeded: true` Expected: Throws "Array limit exceeded" error. Actual: Parses successfully, creating an array of length 26. ### Impact Denial of Service (DoS) via memory exhaustion.
総合評価: CVE-2026-2391 は公開エクスプロイトあり（53.7/100）。CVSS 深刻度は中。悪用される可能性が高い（EPSS 0.48%、37 パーセンタイル） 根拠: 公開エクスプロイトが 1 件参照されています（Exploit-DB）。 推奨対応: 公開エクスプロイトが確認されています。影響範囲の確認、緩和策の適用、パッチ適用を優先してください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
| EDB-ID | ソース | 種別 | 公開 | リンク |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.06% | 0.48% | +0.42% |
| 2 | 2026-03-26 | 0.05% | 0.06% | +0.01% |
| 3 | 2026-02-12 | — | 0.05% | — |
EPSS の全履歴 （全 3 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 6.3 | 4.0 | MEDIUM |
|
— | — | 7ffcee3d-2c14-4c3e-b844-86c6a321a158 |
| 3.7 | 3.1 | LOW |
|
2.2 | 1.4 | 7ffcee3d-2c14-4c3e-b844-86c6a321a158 |
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
GHSA-w7fw-mjwx-w883 · 深刻度： low · エコシステム： npm — qs's arrayLimit bypass in comma parsing allows denial of service
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2026-2391 not yet assigned priority: Debian including 1 source packages (node-qs), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. | https://security-tracker.debian.org/tracker/CVE-2026-2391 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2026-2391 |
ubuntu
|
medium | CVE-2026-2391 medium priority: Ubuntu including 1 source packages (node-qs), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): needs-triage 8. | https://ubuntu.com/security/CVE-2026-2391 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| qs_project | qs | >= 6.7.0, < 6.14.2 | cpe:2.3:a:qs_project:qs:*:*:*:*:*:node.js:*:* |
| URL | タグ |
|---|---|
| https://github.com/ljharb/qs/commit/f6a7abff1f13d644db9b05fe4f2c98ada6bf8482 | Patch |
| https://github.com/ljharb/qs/security/advisories/GHSA-w7fw-mjwx-w883 | Exploit Vendor Advisory |