Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
No advisories yet.
Fri, 21 Aug 2026 11:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Thu, 20 Aug 2026 22:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | The URLS regular expression in nltk/tokenize/casual.py, compiled into TweetTokenizer.WORD_RE and applied by TweetTokenizer.tokenize, contains a naked-domain branch whose domain-label prefix [a-z0-9]+(?:[.\-][a-z0-9]+)* is unbounded. Input consisting of many alternating label separators can be partitioned in exponentially many ways, and because the branch also requires a trailing top-level domain that such input never supplies, the engine explores those partitions before failing at each offset. A few kilobytes of input therefore consumes seconds to minutes of single-threaded CPU, and the HANG_RE substitution performed before matching does not collapse the pattern. TweetTokenizer is intended for tokenizing untrusted social-media text, so any service that applies it, or the module-level casual_tokenize, to submitted text can be stalled per request without authentication. Version 3.10.1 bounds the label repetition. | |
| Title | NLTK TweetTokenizer URL Pattern Backtracks Catastrophically on Naked-Domain-Like Input | |
| First Time appeared |
Nltk
Nltk nltk |
|
| Weaknesses | CWE-1333 | |
| CPEs | cpe:2.3:a:nltk:nltk:3.6.5:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.6.6:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.6.7:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.7:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.8.1:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.8:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.9.1:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.9.2:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.9.3:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.9:*:*:*:*:*:*:* cpe:2.3:a:nltk:nltk:3.9:beta1:*:*:*:*:*:* |
|
| Vendors & Products |
Nltk
Nltk nltk |
|
| References |
|
|
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-08-21T11:20:57.674Z
Reserved: 2026-08-10T15:12:16.754Z
Link: CVE-2026-72818
Updated: 2026-08-21T11:06:02.698Z
Status : Received
Published: 2026-08-20T22:18:05.087
Modified: 2026-08-21T11:17:05.920
Link: CVE-2026-72818
No data.
OpenCVE Enrichment
Updated: 2026-08-21T01:15:06Z
-
CWE-1333
Inefficient Regular Expression Complexity