# CVE-2026-52840: Easy!Appointments has server-side request forgery in CalDAV connection test that exposes the deployment's internal network

> A logged-in user can exploit a CalDAV connection test to perform server-side request forgery, accessing internal network resources and reading response data.

- **Severity:** Low 2.7 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-pm5p-7w5h-jm5q

## What is CVE-2026-52840?

CVE-2026-52840 is a low-severity server-side request forgery vulnerability in alextselegidis easyappointments, published on 14 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Easy!Appointments is a self hosted appointment scheduler. In versions prior to 1.6.0, `Caldav::connect_to_server` at `application/controllers/Caldav.php:60` hands the request's `caldav_url` to a Guzzle `REPORT` call without scheme or host validation. A logged-in backend user (admin, provider, or secretary) reaches loopback, RFC1918, and link-local hosts on the deployment's network. The Guzzle exception path returns the upstream status code plus ~120 bytes of response body in the JSON `message` field (`Caldav.php:74-78`), so the SSRF is semi-blind. Version 1.6.0 contains a patch.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-52840?

2 open source packages ship an affected version, including alextselegidis/easyappointments.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `alextselegidis/easyappointments` | Packagist | All versions to 1.5.2 | None |
| `alextselegidis/easyappointments` | Packagist | All versions to 1.5.2 | None |

## How do I fix CVE-2026-52840?

No fix has been published for CVE-2026-52840 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-52840 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52840 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52840 and fix it if it is affected.

What it is: CVE-2026-52840 is a low-severity server-side request forgery vulnerability in alextselegidis easyappointments, published on 14 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52840 exists.

Affected packages and fixed versions:
- alextselegidis/easyappointments (Packagist): affected all versions up to 1.5.2; no fix listed
- alextselegidis/easyappointments (Packagist): affected all versions up to 1.5.2; no fix listed

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-2026-52840/ (Markdown: https://insights.sbomify.com/CVE-2026-52840/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52840
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52840
- OSV: https://osv.dev/vulnerability/CVE-2026-52840

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52840/
Summaries are generated and may contain mistakes; the official description above is the record.