Advisory details:
gitlab / pypi/nltk/CVE-2026-12061
| Advisory ID | gitlab/pypi/nltk/CVE-2026-12061 |
| Aliases |
CVE-2026-12061
GHSA-fg7f-2386-8897 |
| Summary | Natural Language Toolkit (NLTK): ReDoS in NLTK ReviewsCorpusReader FEATURES regex `ReviewsCorpusReader` extracts feature annotations of the form *label* followed by a bracketed signed digit (e.g. a label then `[+2]`) from each review line, using the module-level `FEATURES` regex. The feature-label sub-pattern is unbounded — an optional greedy run of word-plus-whitespace groups followed by another word, which must then be followed by a literal `[`. On a long bracket-less line the label can match from every search position to the end of the line, causing quadratic backtracking. A single crafted line in a reviews corpus hangs `reviews()`, `features()`, and `sents()`. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 0.0 |
| Risk | |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-12061.yml |
| Reference id | Reference type | URL |
|---|---|---|
| https://github.com/advisories/GHSA-fg7f-2386-8897 | ||
| https://github.com/nltk/nltk/security/advisories/GHSA-fg7f-2386-8897 | ||
| https://nvd.nist.gov/vuln/detail/CVE-2026-12061 |
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.