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Case File

CVE-2021-41258

HIGH · CVSS 7.3 EPSS 0.78% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-11-16 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 7.3. 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.

Detected Signals
exploit

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

CVE
CVE-2021-41258
Severity
HIGH
CVSS
7.3
EPSS
0.78%

Original NVD Description

Kirby is an open source file structured CMS. In affected versions Kirby's blocks field stores structured data for each block. This data is then used in block snippets to convert the blocks to HTML for use in your templates. We recommend to escape HTML special characters to protect against cross-site scripting (XSS) attacks. The default snippet for the image block unfortunately did not use our escaping helper. This made it possible to include malicious HTML code in the source, alt and link fields of the image block, which would then be displayed on the site frontend and executed in the browsers of site visitors and logged in users who are browsing the site. Attackers must be in your group of authenticated Panel users in order to exploit this weakness. Users who do not make use of the blocks field are not affected. This issue has been patched in Kirby version 3.5.8 by escaping special HTML characters in the output from the default image block snippet. Please update to this or a later version to fix the vulnerability.

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