XSS in Getkirby Kirby
CVE-2021-41252
Kirby is an open source file structured CMS ### Impact Kirby's writer field stores its formatted content as HTML code. Unlike with other field types, it is not possible to escape HTML special characters against cross-site scripting (XSS) attacks, otherwise the formatting would be lost. If the user is logged in to the Panel, a harmful script can for example trigger requests to Kirby's API with the permissions of the victim. Because the writer field did not securely sanitize its contents on save, it was possible to inject malicious HTML code into the content file by sending it to Kirby's API directly without using the Panel. This malicious HTML code 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 writer field are not affected. This issue has been patched in Kirby 3.5.8 by sanitizing all writer field contents on the backend whenever the content is modified via Kirby's API. Please update to this or a later version to fix the vulnerability.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.009 (57.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 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.
Affected products
- Getkirby Kirby — versions >= 3.5.0, < 3.5.8
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2021-41252?
- CVE-2021-41252 is a high-severity vulnerability in Getkirby Kirby, classified under Cross-site Scripting. CVSS score: 7.3/10. Published 2021-11-16.
- How severe is CVE-2021-41252?
- High severity. CVSS v3 base score is 7.3 out of 10.
- Is CVE-2021-41252 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.