Read the docs
TI-2023-19871 Aliases CVE-2023-38491GHSA-8fv7-wq38-f5c9

Kirby vulnerable to Cross-site scripting (XSS) from MIME type auto-detection of uploaded files

Priority LOW 27CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0062 49th percentileScored 2026-11-07
Fix Fixed kirby (getkirby): 3.5.8.3, 3.6.6.3, 3.7.5.2 +2getkirby/cms (Packagist): 3.5.8.3, 3.6.6.3, 3.7.5.2 +2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
getkirbykirbybefore 3.5.8.3; 3.6.0 to before 3.6.6.3; 3.7.0 to before 3.7.5.2; 3.8.0 to before 3.8.41; 3.9.0 to before 3.9.63.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.41, 3.9.6Patch availableCNA
—getkirby/cms (Packagist)before 3.5.8.33.5.8.3Patch availableGHSA-8fv7-wq38-f5c9
—getkirby/cms (Packagist)3.6.0 to before 3.6.6.33.6.6.3Patch availableGHSA-8fv7-wq38-f5c9
—getkirby/cms (Packagist)3.7.0 to before 3.7.5.23.7.5.2Patch availableGHSA-8fv7-wq38-f5c9
—getkirby/cms (Packagist)3.8.0 to before 3.8.4.13.8.4.1Patch availableGHSA-8fv7-wq38-f5c9
—getkirby/cms (Packagist)3.9.0 to before 3.9.63.9.6Patch availableGHSA-8fv7-wq38-f5c9
  • kirby Vendorgetkirby Affected before 3.5.8.3; 3.6.0 to before 3.6.6.3; 3.7.0 to before 3.7.5.2; 3.8.0 to before 3.8.41; 3.9.0 to before 3.9.6 Fixed in 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.41, 3.9.6 Patch available CNA
  • getkirby/cms (Packagist) Vendor— Affected before 3.5.8.3 Fixed in 3.5.8.3 Patch available GHSA-8fv7-wq38-f5c9
  • getkirby/cms (Packagist) Vendor— Affected 3.6.0 to before 3.6.6.3 Fixed in 3.6.6.3 Patch available GHSA-8fv7-wq38-f5c9
  • getkirby/cms (Packagist) Vendor— Affected 3.7.0 to before 3.7.5.2 Fixed in 3.7.5.2 Patch available GHSA-8fv7-wq38-f5c9
  • getkirby/cms (Packagist) Vendor— Affected 3.8.0 to before 3.8.4.1 Fixed in 3.8.4.1 Patch available GHSA-8fv7-wq38-f5c9
  • getkirby/cms (Packagist) Vendor— Affected 3.9.0 to before 3.9.6 Fixed in 3.9.6 Patch available GHSA-8fv7-wq38-f5c9

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:*3.5.0 to before 3.5.8.3; 3.6.0 to before 3.6.6.3; 3.7.0 to before 3.7.5.2; 3.8.0 to before 3.8.4.1; 3.9.0 to before 3.9.6Vulnerablegetkirby
  • cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:* Versions 3.5.0 to before 3.5.8.3; 3.6.0 to before 3.6.6.3; 3.7.0 to before 3.7.5.2; 3.8.0 to before 3.8.4.1; 3.9.0 to before 3.9.6 Vulnerable ·getkirby

Remediation

  • Fix · CNA kirby (getkirby) Fixed in 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.41, 3.9.6
  • Fix · GHSA-8fv7-wq38-f5c9 getkirby/cms (Packagist) Fixed in 3.5.8.3 Advisory →
  • Fix · GHSA-8fv7-wq38-f5c9 getkirby/cms (Packagist) Fixed in 3.6.6.3 Advisory →
  • Fix · GHSA-8fv7-wq38-f5c9 getkirby/cms (Packagist) Fixed in 3.7.5.2 Advisory →
  • Fix · GHSA-8fv7-wq38-f5c9 getkirby/cms (Packagist) Fixed in 3.8.4.1 Advisory →
  • Fix · GHSA-8fv7-wq38-f5c9 getkirby/cms (Packagist) Fixed in 3.9.6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-38491
  2. 2026-10-03 Alias added: GHSA-8fv7-wq38-f5c9

References

Patch 1

Advisory 7

Other 1

  • TI-2024-17440 An arbitrary file upload vulnerability in the Profile Image module of Kirby CMS v4.1.0… CVSS 3.1HIGH 8.8
  • TI-2024-17439 An HTML injection vulnerability exists in the Edit Content Layout module of Kirby CMS… CVSS 3.1HIGH 7.1
  • TI-2026-23396 Kirby CMS through 5.1.4 allows an authenticated user with 'Editor' permissions to cause a… CVSS 3.1MEDIUM 6.5
  • TI-2024-17441 A stored cross-site scripting (XSS) vulnerability in the Edit Content Layout module of… CVSS 3.1MEDIUM 6.1
  • TI-2018-10413 An issue was discovered in Kirby 2.5.12. CVSS 3.1MEDIUM 5.4
  • TI-2024-17438 Kirby CMS v4.1.0 was discovered to contain a reflected self-XSS vulnerability via the URL parameter. CVSS 3.1MEDIUM 4.7
See all 40 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences