# CVE-2025-8533: Incorrect Authorization of XPC Service in Fantastical.app

> Local attackers can access Fantastical XPC services due to missing authorization checks, potentially reading or modifying calendar data.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Aug 2025
- **Updated:** 7 Aug 2025
- **Also known as:** GHSA-8g5c-fvxq-mw4m

## What is CVE-2025-8533?

CVE-2025-8533 is a medium-severity missing authorization vulnerability in Flexibits Fantastical, published on 7 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was identified in the XPC services of Fantastical. The services failed to implement proper client authorization checks in its listener:shouldAcceptNewConnection method, unconditionally accepting requests from any local process. As a result, any local, unprivileged process could connect to the XPC service and access its methods.

This issue has been resolved in version 4.0.16.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2025-8533?


## How do I fix CVE-2025-8533?

No fix has been published for CVE-2025-8533 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-8533 being exploited?

There is no known exploitation of CVE-2025-8533 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-8533 and fix it if it is affected.

What it is: CVE-2025-8533 is a medium-severity missing authorization vulnerability in Flexibits Fantastical, published on 7 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-8533 in the wild and no public exploit code.

Affected product: Flexibits Fantastical. 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-2025-8533/ (Markdown: https://insights.sbomify.com/CVE-2025-8533/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-8533
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-8533
- OSV: https://osv.dev/vulnerability/CVE-2025-8533

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-8533/
Summaries are generated and may contain mistakes; the official description above is the record.