CVE-2023-38492: Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites with ...

Description

Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites with user accounts (unless Kirby's API and Panel are disabled in the config). The real-world impact of this vulnerability is limited, however we still recommend to update to one of the patch releases because they also fix more severe vulnerabilities. Kirby's authentication endpoint did not limit the password length. This allowed attackers to provide a password with a length up to the server's maximum request body length. Validating that password against the user's actual password requires hashing the provided password, which requires more CPU and memory resources (and therefore processing time) the longer the provided password gets. This could be abused by an attacker to cause the website to become unresponsive or unavailable. Because Kirby comes with a built-in brute force protection, the impact of this vulnerability is limited to 10 failed logins from each IP address and 10 failed logins for each existing user per hour. The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have added password length limits in the affected code so that passwords longer than 1000 bytes are immediately blocked, both when setting a password and when logging in.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.03%

59.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Getkirby	Kirby	>= 3.5.0, < 3.5.8.3
Getkirby	Kirby	>= 3.6.0, < 3.6.6.3
Getkirby	Kirby	>= 3.7.0, < 3.7.5.2
Getkirby	Kirby	>= 3.8.0, < 3.8.4.1
Getkirby	Kirby	>= 3.9.0, < 3.9.6

References

https://github.com/getkirby/kirby/commit/0e10ce3b0c2b88656564b8ff518ddc99136ac43eThird Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.5.8.3Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.6.6.3Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.7.5.2Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.8.4.1Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.9.6Third Party Advisory
https://github.com/getkirby/kirby/security/advisories/GHSA-3v6j-v3qc-cxffThird Party Advisory
https://github.com/getkirby/kirby/commit/0e10ce3b0c2b88656564b8ff518ddc99136ac43eThird Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.5.8.3Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.6.6.3Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.7.5.2Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.8.4.1Third Party Advisory
https://github.com/getkirby/kirby/releases/tag/3.9.6Third Party Advisory
https://github.com/getkirby/kirby/security/advisories/GHSA-3v6j-v3qc-cxffThird Party Advisory

Timeline

Published: Jul 27, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-38492?

Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites with user accounts (unless Kirby's API and Panel are disabled in the config). The real-world impact of this vulnerability is limited, however we still recommend to update to one of the patch releases because they also fix more severe vulnerabilities. Kirby's authentication endpoint did not limit the password length. This allowed attackers to provide a password with a length up to the server's maximum request body length. Validating that password against the user's actual password requires hashing the provided password, which requires more CPU and memory resources (and therefore processing time) the longer the provided password gets. This could be abused by an attacker to cause the website to become unresponsive or unavailable. Because Kirby comes with a built-in brute force protection, the impact of this vulnerability is limited to 10 failed logins from each IP address and 10 failed logins for each existing user per hour. The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have added password length limits in the affected code so that passwords longer than 1000 bytes are immediately blocked, both when setting a password and when logging in.

How severe is CVE-2023-38492?

CVE-2023-38492 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2023-38492?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.