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

> Attackers can execute arbitrary scripts in the site frontend via malicious URLs in KirbyTags and image blocks, requiring an upgrade to patched versions.

- **Severity:** High 8.4 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Jul 2026
- **Updated:** 18 Jul 2026
- **Also known as:** GHSA-qvjf-922g-pj44

## What is CVE-2026-45368?

CVE-2026-45368 is a high-severity cross-site scripting vulnerability in getkirby kirby, published on 16 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-45368?

4 open source packages ship an affected version, including getkirby/cms.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `getkirby/cms` | Packagist | All versions | 4.9.1 |
| `getkirby/cms` | Packagist | All versions | 4.9.1 |
| `getkirby/cms` | Packagist | From 5.0.0 | 5.4.1 |
| `getkirby/cms` | Packagist | From 5.0.0 | 5.4.1 |

## How do I fix CVE-2026-45368?

Upgrade getkirby/cms to a fixed version for your release line: 4.9.1 or 5.4.1.

## Is CVE-2026-45368 being exploited?

There is no known exploitation of CVE-2026-45368 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45368 and fix it if it is affected.

What it is: CVE-2026-45368 is a high-severity cross-site scripting vulnerability in getkirby kirby, published on 16 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-45368 in the wild and no public exploit code.

Affected packages and fixed versions:
- getkirby/cms (Packagist): affected all versions; fixed in 4.9.1
- getkirby/cms (Packagist): affected all versions; fixed in 4.9.1
- getkirby/cms (Packagist): affected from 5.0.0; fixed in 5.4.1
- getkirby/cms (Packagist): affected from 5.0.0; fixed in 5.4.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-45368/ (Markdown: https://insights.sbomify.com/CVE-2026-45368/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45368
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45368
- OSV: https://osv.dev/vulnerability/CVE-2026-45368

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45368/
Summaries are generated and may contain mistakes; the official description above is the record.