NLTK up to 3.6.4 Regular Expression resource consumption

CVSS Meta Temp Score
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CTI Interest Score
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6.3$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in NLTK up to 3.6.4. This affects the function PunktSentenceTokenizer/sent_tokenize/word_tokenize of the component Regular Expression Handler. The manipulation leads to resource consumption. This vulnerability is traded as CVE-2021-43854. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in NLTK up to 3.6.4. It has been rated as problematic. This issue affects the function PunktSentenceTokenizer/sent_tokenize/word_tokenize of the component Regular Expression Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability.

The weakness was shared 12/23/2021 as GHSA-f8m6-h2c7-8h9x. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2021-43854 since 11/16/2021. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 233286 (Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS : NLTK vulnerabilities (USN-7365-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.6.5 eliminates this vulnerability. Applying the patch 1405aad979c6b8080dbbc8e0858f89b2e3690341 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (233286). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (GitHub, Inc.): 🔍

CVSSv2info

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

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 233286
Nessus Name: Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS : NLTK vulnerabilities (USN-7365-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: NLTK 3.6.5
Patch: 1405aad979c6b8080dbbc8e0858f89b2e3690341

Timelineinfo

11/16/2021 🔍
12/23/2021 +37 days 🔍
12/23/2021 +0 days 🔍
03/24/2025 +1187 days 🔍

Sourcesinfo

Product: github.com

Advisory: GHSA-f8m6-h2c7-8h9x
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-43854 (🔍)
GCVE (CVE): GCVE-0-2021-43854
GCVE (VulDB): GCVE-100-188999

Entryinfo

Created: 12/23/2021 22:02
Updated: 03/24/2025 16:10
Changes: 12/23/2021 22:02 (52), 12/26/2021 15:14 (2), 03/24/2025 16:10 (16)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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