Vulnerability Description
NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader directory can create hardlinks pointing to outside-root files that are then overwritten during normal package extraction, mutating files outside the intended install tree.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nltk | Nltk | < 3.10.3 |
Related Weaknesses (CWE)
References
- https://github.com/nltk/nltk/security/advisories/GHSA-f794-5jv7-7672ExploitVendor Advisory
- https://www.vulncheck.com/advisories/nltk-before-3.10.3-hardlink-file-overwrite-Third Party Advisory
- https://github.com/nltk/nltk/security/advisories/GHSA-f794-5jv7-7672ExploitVendor Advisory
FAQ
What is CVE-2026-81727?
CVE-2026-81727 is a vulnerability with a CVSS score of 7.1 (HIGH). NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that allows attackers to overwrite files outside the i...
How severe is CVE-2026-81727?
CVE-2026-81727 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-81727?
Check the references section above for vendor advisories and patch information. Affected products include: Nltk Nltk.