# CVE-2026-89289: Fast Courier <= 5.2.3 - Unauthenticated Order Fulfillment Update via order-status-update REST Endpoint

> Unauthenticated attackers can modify WooCommerce order fulfillment status and tracking details via an unprotected REST endpoint in the Fast Courier plugin.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Oct 2026
- **Updated:** 6 Oct 2026
- **Also known as:** GHSA-r2m9-vxc3-w8ph

## What is CVE-2026-89289?

CVE-2026-89289 is a medium-severity missing authorization vulnerability in Unknown Fast Courier, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Fast Courier  WordPress plugin through 5.2.3 does not restrict an unauthenticated REST route that writes order fulfillment data, allowing unauthenticated attackers to overwrite the courier status and customer-facing tracking details of any WooCommerce order by supplying its id.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-89289?


## How do I fix CVE-2026-89289?

No fix has been published for CVE-2026-89289 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-89289 being exploited?

There is no known exploitation of CVE-2026-89289 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89289 and fix it if it is affected.

What it is: CVE-2026-89289 is a medium-severity missing authorization vulnerability in Unknown Fast Courier, published on 6 Oct 2026. 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-2026-89289 in the wild and no public exploit code.

Affected product: Unknown Fast Courier. 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-2026-89289/ (Markdown: https://insights.sbomify.com/CVE-2026-89289/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89289
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89289
- OSV: https://osv.dev/vulnerability/CVE-2026-89289

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89289/
Summaries are generated and may contain mistakes; the official description above is the record.