CVE-2023-38491

What it is

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 that might have potential attackers in the group of authenticated Panel users or that allow external visitors to upload an arbitrary file to the content folder. Kirby sites are not affected if they don't allow file uploads for untrusted users or visitors or if the file extensions of uploaded files are limited to a fixed safe list. The attack requires user interaction by another user or visitor and cannot be automated. An editor with write access to the Kirby Panel could upload a file with an unknown file extension like `.xyz` that contains HTML code including harmful content like `<script>` tags. The direct link to that file could be sent to other users or visitors of the site. If the victim opened that link in a browser where they are logged in to Kirby and the file had not been opened by anyone since the upload, Kirby would not be able to send the correct MIME content type, instead falling back to `text/html`. The browser would then run the script, which could for example trigger requests to Kirby's API with the permissions of the victim. The issue was caused by the underlying `Kirby\Http\Response::file()` method, which didn't have an explicit fallback if the MIME type could not be determined from the file extension. If you use this method in site or plugin code, these uses may be affected by the same vulnerability. 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 fixed the affected method to use a fallback MIME type of `text/plain` and set the `X-Content-Type-Options: nosniff` header if the MIME type of the file is unknown.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-07-27 16:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.6% in the next 30 days (EPSS).
• Severity: 5.7 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-07-27 16:15 UTC

Last modified

2026-06-17 06:10 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-79 · Cross-site scripting

Record status

Modified

Affected

• Getkirby Kirby < 3.5.8.3
• Getkirby Kirby < 3.6.6.3
• Getkirby Kirby < 3.7.5.2
• Getkirby Kirby < 3.8.4.1
• Getkirby Kirby < 3.9.6

Attack profile CVSS 3.1 · 5.7

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-38491.md and follow it. Check whether this project is affected by CVE-2023-38491. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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