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CVE-2026-13311 high CVSS 7.5

Vulnerability in shell-quote (CVE-2026-13311)

Summary

Vulnerability in shell-quote (CVE-2026-13311). Risk of unauthorized operations or information disclosure. Exploitable via GET /ping. Mitigation: upgrade to 1.9.0 or later.

Original description

The description as published by the source.

Summary

shell-quote's parse() finalizes its token list with a reduce that uses
Array.prototype.concat as the accumulator. Each prev.concat(arg) copies the entire growing
array, so parse() runs in O(n²) in the number of tokens. An unauthenticated attacker who
can submit a string to any code path that calls parse() on it can block the single-threaded
Node.js event loop for tens of seconds with a small input — a denial of service. The trigger
needs no shell metacharacters (plain space-separated words suffice), so input filters that
only screen for ;, |, $, or backticks do not help.

Root cause

parse.js (lines 200–203), in parseInternal — this path runs on every parse() call:

}).reduce(function (prev, arg) { // finalize parsed arguments
    // TODO: replace this whole reduce with a concat
    return typeof arg === 'undefined' ? prev : prev.concat(arg);
}, []);

prev.concat(arg) allocates a new array and copies all of prev on every iteration, so
producing an N-token result costs 1 + 2 + … + N = O(N²) copies. A second acc.concat(s)
reduce in the module.exports wrapper (lines 211–224, reached only when env is a function)
has the same shape. The maintainer's own // TODO: replace this whole reduce with a concat
already flags the construct.

Proof of Concept

const { parse } = require('shell-quote');
const ms = fn => { const t = process.hrtime.bigint(); fn(); return Number(process.hrtime.bigint()-t)/1e6; };…

Source: NIST National Vulnerability Database 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-2026-13311 has been found in shell-quote.
Attackers can target a specific entry point like GET /ping over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade shell-quote to 1.9.0 or later.
If unsure, ask your IT team or search "shell-quote CVE-2026-13311" on the vendor's site.

CVE-2026-13311 (shell-quote) — CWE-407 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: GET /ping / reduce / Array.prototype.concat / parse.js
Patched: 1.9.0 — 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.

❓ What is the problem

A vulnerability (CWE-407) exists in shell-quote. Attackers reach the vulnerable code path via GET /ping without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of shell-quote. Attack surface: GET /ping / reduce / Array.prototype.concat / parse.js.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.9.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual GET /ping requests with malformed payloads or SQL meta-characters. Run grep -r 'shell-quote' . 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

  1. 1
    Identify exposure identify 
    grep -r 'shell-quote' . | 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 shell-quote を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'GET /ping' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで GET /ping への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch 
    Upgrade shell-quote to 1.9.0

    ステージング環境で 1.9.0 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と、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify 
    Replay attack against GET /ping on staging to confirm patch closes the vector

    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 Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

npm shell-quote
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.0"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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