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Echo: mistune: security update to 3.3.0

high Tenable Self-Hosted Container Security Plugin ID 459986

Description

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

 - Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a
 CPU exhaustion DoS due to superlinear (approximately O(n²)) behavior in parse_link_text. When parsing
 Markdown containing many consecutive [ characters, parse_link_text repeatedly scans the input using a
 regex search inside a loop. Each iteration re-scans a large portion of the remaining string, resulting in
 quadratic-time behavior. An attacker-controlled Markdown input can therefore trigger excessive CPU usage
 with a very small payload. This vulnerability is fixed in 3.3.0. (CVE-2026-49851)

Solution

Update the mistune library and its related packages to version 3.3.0 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-49851

Plugin Details

Severity: High

ID: 459986

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/5/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.71

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-49851

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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:U/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.6

Threat Vector: CVSS:4.0/E:U

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 Ease: No known exploits are available

Patch Publication Date: 7/11/2026

Vulnerability Publication Date: 6/24/2026

Reference Information

CVE: CVE-2026-49851