Answer in brief
CVE-2026-79657 records a Critical severity (CVSS 9.3) vulnerability in NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization. The current sources do not mark it as known exploited. The current feed maps nltk/nltk (generic), nltk (pip), nltk (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps nltk/nltk (generic), nltk (pip), nltk (pypi). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| nltk/nltkgeneric | >=0 <3.10.3 | 3.10.3 |
| nltkpip | <=3.10.2 | 3.10.3 |
| nltkpypi | >=0 <3.10.3 | 3.10.3 |
Published upstream
Aug 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 25, 2026
NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables. Attackers can craft malicious pickle payloads invoking dangerous in-namespace functions like ReppTokenizer._execute and numpy.f2py.crackfortran.myeval through pickle REDUCE to execute arbitrary commands during model or tokenizer artifact loading.
Quoted source text, attributed separately from HOL analysis.