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CVE-2026-79657— NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization

Quick assessment

Affected
nltk nltk
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

NLTK 3.10.3 之前的版本中存在远程代码执行漏洞。该漏洞源于白名单 pickle 加载器信任整个模块命名空间,而非仅信任特定的安全可调对象。攻击者可通过构造恶意的 pickle 载荷,利用 pickle 的 REDUCE 机制调用命名空间内危险的函数(例如 和 ),从而在加载模型或分词器(tokenizer)工件时执行任意命令。

CVSS 9.8 · Critical

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 2

VendorProduct Version RangeStatus
nltk nltk < 3.10.3 affected
3.10.3 unaffected
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I. Basic Information for CVE-2026-79657

Vulnerability Information

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Vulnerability Title
NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
可信数据的反序列化
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
nltk nltk 0 ~ 3.10.3 -

II. Public POCs for CVE-2026-79657

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 11441 chars
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III. Intelligence Information for CVE-2026-79657

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Vendor Advisories for CVE-2026-79657 (2)

Same Patch Batch · nltk · 2026-08-25 · 8 CVEs total

CVE-2026-79675 9.8 CRITICAL NLTK before 3.10.3 JVM Argument Injection via Per-Call Options
CVE-2026-78683 9.6 CRITICAL NLTK before 3.10.0 Remote Code Execution via Unsafe Pickle Deserialization
CVE-2026-79674 8.2 HIGH NLTK 3.10.2 Path Traversal via corpus-reader constructors
CVE-2026-78680 7.8 HIGH NLTK before 3.10.3 Arbitrary Code Execution via Graphviz dot Binary
CVE-2026-78681 7.5 HIGH NLTK before 3.10.3 Entity Expansion DoS via ElementTree
CVE-2026-78682 7.5 HIGH NLTK before 3.10.3 SSRF Protection Bypass via Proxy
CVE-2026-79676 5.9 MEDIUM NLTK before 3.10.3 Path Traversal via Symlink Bypass

IV. Related Vulnerabilities

V. Comments for CVE-2026-79657

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