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CVE-2026-63312— NLTK StreamBackedCorpusView Bypasses pathsec.ENFORCE Arbitrary File Read

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是NLTK组织开源的一个自然语言处理工具包。 NLTK 3.10.0之前版本存在路径遍历漏洞，该漏洞源于StreamBackedCorpusView组件直接调用builtins.open()而非pathsec.open()，绕过了pathsec.ENFORCE限制，可能导致控制fileid参数的攻击者读取任意本地文件，包括敏感系统文件和应用程序凭据。

CVSS 7.5 · High EPSS 0.65% · P51

Possible ATT&CK Techniques 1 AI

T1552.004 · Private Keys

Affected Version Matrix 2

VendorProduct Version RangeStatus
nltk nltk < 3.10.0 affected
3.10.0 unaffected
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I. Basic Information for CVE-2026-63312

Vulnerability Information
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Vulnerability Title
NLTK StreamBackedCorpusView Bypasses pathsec.ENFORCE Arbitrary File Read
Source: CVE Program / CVE List V5
Vulnerability Description
NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open(). Attackers who control the fileid argument can read arbitrary local files regardless of the ENFORCE setting, including sensitive system files and application credentials.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Vulnerability Title
NLTK 路径遍历漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
NLTK是NLTK组织开源的一个自然语言处理工具包。 NLTK 3.10.0之前版本存在路径遍历漏洞，该漏洞源于StreamBackedCorpusView组件直接调用builtins.open()而非pathsec.open()，绕过了pathsec.ENFORCE限制，可能导致控制fileid参数的攻击者读取任意本地文件，包括敏感系统文件和应用程序凭据。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
nltk nltk 0 ~ 3.10.0 -

II. Public POCs for CVE-2026-63312

# POC Description Source Link Shenlong Link
AI-Generated POC Verified env Premium
Reproduced successfully in a real sandbox · Below is the actual recording of building the environment and exploiting the vulnerability.
Reproduction recording is a Pro+ exclusive
Watch the full sandbox build + live exploit recording for this CVE. Limited-time ¥499/mo.
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claude_code · 8154 chars
GitHub 复现环境（可 clone 直接跑）
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-63312

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Vendor Advisories for CVE-2026-63312 (2)

Same Patch Batch · nltk · 2026-08-22 · 11 CVEs total

CVE-2026-71513 8.8 HIGH NLTK 3.10.0 through 3.10.2 Remote Code Execution via AllowlistUnpickler Dotted-Name Bypass
CVE-2026-62388 7.5 HIGH NLTK before 3.10.0 Insecure Default Configuration in pathsec.py
CVE-2026-62384 7.5 HIGH NLTK FramenetCorpusReader Symlink Sandbox Bypass before 3.10.2
CVE-2026-66393 7.5 HIGH NLTK before 3.9.4 Denial of Service via JSONTaggedDecoder
CVE-2026-65915 6.5 MEDIUM NLTK before 3.10.0 Arbitrary File Read via FileSystemPathPointer
CVE-2026-70626 6.2 MEDIUM NLTK before 3.9.4 Symlink Escape via CorpusReader
CVE-2026-62385 5.9 MEDIUM NLTK 3.9.4 Path Traversal via FrameNet and NKJP Readers
CVE-2026-62383 5.5 MEDIUM nltk IPIPANCorpusReader Symlink Arbitrary File Read
CVE-2026-63311 5.3 MEDIUM NLTK before 3.10.0 SSRF via DNS Resolution Failure
CVE-2026-71514 2.5 LOW NLTK 3.9.4 through 3.10.2 Path Traversal via CrubadanCorpusReader pathsec Bypass

IV. Related Vulnerabilities

Same product: nltk
Same vendor: nltk
Same weakness: CWE-22

V. Comments for CVE-2026-63312

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