NLTK up to 3.9.x StreamBackedCorpusView builtins.open fileid information disclosure

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k0.87-

Summaryinfo

A vulnerability marked as problematic has been reported in NLTK up to 3.9.x. Affected is the function builtins.open of the component StreamBackedCorpusView. The manipulation of the argument fileid leads to information disclosure. This vulnerability is traded as CVE-2026-63312. An attack has to be approached locally. There is no exploit available.

Detailsinfo

A vulnerability was found in NLTK up to 3.9.x and classified as problematic. This issue affects the function builtins.open of the component StreamBackedCorpusView. The manipulation of the argument fileid with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-63312 since 07/16/2026. The exploitation is known to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1592 for this issue.

Upgrading to version 3.10.0 eliminates this vulnerability.

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Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

VulDB Base Score: 4.0
VulDB Temp Score: 3.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: NLTK 3.10.0

Timelineinfo

07/16/2026 CVE reserved
08/22/2026 +37 days Advisory disclosed
08/22/2026 +0 days VulDB entry created
08/22/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-63312 (🔒)
GCVE (CVE): GCVE-0-2026-63312
GCVE (VulDB): GCVE-100-394349

Entryinfo

Created: 08/22/2026 16:38
Changes: 08/22/2026 16:38 (77)
Complete: 🔍
Cache ID: 216::103

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