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CVE-2021-41258 Detail

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.


Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  5.4 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  7.3 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/getkirby/kirby/pull/3510 Patch  Third Party Advisory 
https://github.com/getkirby/kirby/releases/tag/3.5.8 Release Notes  Third Party Advisory 
https://github.com/getkirby/kirby/security/advisories/GHSA-cq58-r77c-5jjw Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') cwe source acceptance level NIST   Provider acceptance level GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-41258
NVD Published Date:
11/16/2021
NVD Last Modified:
11/18/2021
Source:
GitHub, Inc.