# CVE-2026-14827: Calendar < 1.3.18 - Contributor+ Stored XSS via event_link Parameter

> Contributors can inject JavaScript via the event_link parameter, leading to stored XSS execution in viewers' browsers.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 27 Jul 2026
- **Updated:** 27 Jul 2026
- **Also known as:** GHSA-x423-2wcq-r3qx

## What is CVE-2026-14827?

CVE-2026-14827 is a medium-severity cross-site scripting vulnerability in Unknown Calendar, published on 27 Jul 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

The Calendar WordPress plugin before 1.3.18 does not properly escape a user-supplied event field before outputting it inside an HTML attribute on a public-facing page, allowing users with the Contributor role to inject arbitrary JavaScript that executes in the browser of anyone viewing the calendar.

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

## Which versions are affected by CVE-2026-14827?


## How do I fix CVE-2026-14827?

No fix has been published for CVE-2026-14827 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-14827 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-14827 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-14827 and fix it if it is affected.

What it is: CVE-2026-14827 is a medium-severity cross-site scripting vulnerability in Unknown Calendar, published on 27 Jul 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-14827 exists.

Affected product: Unknown Calendar. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-14827/ (Markdown: https://insights.sbomify.com/CVE-2026-14827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-14827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-14827
- OSV: https://osv.dev/vulnerability/CVE-2026-14827

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-14827/
Summaries are generated and may contain mistakes; the official description above is the record.