CVE-2026-59710 | showdown contains a stored cross-site scripting vulnerabilit… | CVSS 6.1 MEDIUM

Description

showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.

Metadata

CVE ID: CVE-2026-59710
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-07-06 15:31 UTC
Published: 2026-07-06 21:15 UTC
Last updated: 2026-07-07 00:09 UTC
Primary CWE: CWE-79
Improper Neutralization of Input During Web Page Generation …
Vendor / Product: showdown / showdown
Sources: cve.org · NVD

Severity & Metrics

6.1 MEDIUM CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products (1)

Vendor	Product	Platform	Versions
showdown	showdown	—	0 ≤ 2.1.0

Weakness (CWE)

CWE	Source	Description
CWE-79	cna	Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS scores (2)

Score	Severity	Version	Source	Vector
6.1	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.3	MEDIUM	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

References (4)