CVSS 4.0
8.7 highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCVE-2026-80205
High (8.7) in nltk nltk. EPSS 0.7% chance of exploitation in the next 30 days. Fixed in nltk 3.10.0.
NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and TokenSearcher.findall() methods that accept user-supplied regular expressions without validation or timeout. Attackers can supply crafted regex patterns that cause catastrophic backtracking, resulting in indefinite CPU saturation and denial of service to all users of the Python process.
Severity
CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- EPSS
- 0.7% chance of exploitation in the next 30 days; higher than 51% of CVEs (scores of 2026-10-31)
- CWE
- CWE-1333
- Published
- Modified
- Record from
- the NVD, synced
Affected
- nltk:nltk
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-rrv8-h7p8-rx55 | PyPI | nltk | <3.10.0 | 3.10.0 |
| PYSEC-2026-3750 | PyPI | nltk | <3.10.0 | 3.10.0 |