Detections
Analytics

Echo: nltk: security update to 3.9.4

high Tenable Cloud Security Plugin ID 459825

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj()
 that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can
 craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionError that crashes the
 Python process. (CVE-2026-66393)

Solution

Update the nltk library and its related packages to version 3.9.4 or later.

Plugin Details

Severity: High

ID: 459825

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/3/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.61

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-66393

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 7.7

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 9/3/2026

Vulnerability Publication Date: 3/18/2026

Reference Information

CVE: CVE-2026-66393