AUGUST 4, 2026
Live Feed
Back to database
Case File

CVE-2021-26540

MEDIUM · CVSS 5.3 EPSS 1.75% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-02-08 · Last synced 2026-08-04

CyberRota Analysis

This is a medium severity vulnerability with a CVSS score of 5.3. Public exploit code or proof-of-concept references have been detected in its references.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2021-26540
Severity
MEDIUM
CVSS
5.3
EPSS
1.75%

Original NVD Description

Apostrophe Technologies sanitize-html before 2.3.2 does not properly validate the hostnames set by the "allowedIframeHostnames" option when the "allowIframeRelativeUrls" is set to true, which allows attackers to bypass hostname whitelist for iframe element, related using an src value that starts with "/\\example.com".

Related CVEs

Other vulnerabilities affecting the same vendor(s)