Vulnerability Description
decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkname field from the archive is passed directly to fs.link() without validation (index.js line 113). An attacker can craft an archive with a hardlink entry whose linkname is an absolute path to any file on the same filesystem. This creates a hardlink inside the extraction directory that shares the same inode as the target file, enabling both reading and overwriting the original file's content. Hardlinks are limited to files on the same filesystem and cannot target directories.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Decompress Project | Decompress | <= 4.2.1 |
Related Weaknesses (CWE)
References
- https://github.com/kevva/decompressProduct
- https://github.com/kevva/decompress/issues/113ExploitVendor Advisory
- https://www.npmjs.com/package/decompressProduct
- https://github.com/kevva/decompress/issues/113ExploitVendor Advisory
FAQ
What is CVE-2026-39243?
CVE-2026-39243 is a vulnerability with a CVSS score of 5.5 (MEDIUM). decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkn...
How severe is CVE-2026-39243?
CVE-2026-39243 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39243?
Check the references section above for vendor advisories and patch information. Affected products include: Decompress Project Decompress.