Advisory details:
github_osv / GHSA-pv39-qrfq-g8gc
| Advisory ID | github_osv/GHSA-pv39-qrfq-g8gc |
| Aliases | |
| Summary | Duplicate Advisory: NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection ## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-5wp5-5229-5g6q. This link is maintained to preserve external references. ## Original Description In nltk version 3.9.4, the `nltk.downloader.Downloader._download_package()` function writes downloaded package bytes to disk and may extract them before enforcing SHA-256 or MD5 checksum validation. This allows an attacker to tamper with the package response body for `info.url` through a compromised mirror, malicious proxy, or other source-substitution condition, leading to the installation of attacker-controlled package bytes. The vulnerability can result in malicious corpus or model content being trusted by downstream users or applications. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 4.8 |
| Risk | 2.4 |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| System | Score | Found at |
|---|---|---|
| cvssv3 | 5.3 | https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-pv39-qrfq-g8gc/GHSA-pv39-qrfq-g8gc.json |
| generic_textual | MODERATE |
| Reference id | Reference type | URL |
|---|---|---|
| 659ccf6d-12d4-4d4a-84c0-078633c35a5d | Other | https://huntr.com/bounties/659ccf6d-12d4-4d4a-84c0-078633c35a5d |
| CVE-2026-12259 | https://nvd.nist.gov/vuln/detail/CVE-2026-12259 |
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
There are no SSVC decisions available.