# CVE-2026-103311: Security feature bypass in Coinbase Commerce Payment Gateway for WooCommerce

> Unauthenticated attackers can forge payment webhooks to mark orders as paid or cancel them due to missing signature validation with an empty default secret.

- **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:** 19 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-cx3h-5fq4-rp7v

## What is CVE-2026-103311?

CVE-2026-103311 is a medium-severity vulnerability in Unknown Coinbase Commerce Payment Gateway for WooCommerce, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Coinbase Commerce Payment Gateway for WooCommerce WordPress plugin through 1.4.1 does not verify the authenticity of incoming payment webhook notifications, because the shared secret used to validate the request signature is empty by default and nothing rejects an unconfigured secret, allowing unauthenticated attackers to forge notifications that mark arbitrary orders as paid or cancel already-paid orders.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-103311?


## How do I fix CVE-2026-103311?

No fix has been published for CVE-2026-103311 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103311 being exploited?

There is no known exploitation of CVE-2026-103311 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103311 and fix it if it is affected.

What it is: CVE-2026-103311 is a medium-severity vulnerability in Unknown Coinbase Commerce Payment Gateway for WooCommerce, published on 19 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-2026-103311 in the wild and no public exploit code.

Affected product: Unknown Coinbase Commerce Payment Gateway for WooCommerce. 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-2026-103311/ (Markdown: https://insights.sbomify.com/CVE-2026-103311/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103311
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103311
- OSV: https://osv.dev/vulnerability/CVE-2026-103311

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103311/
Summaries are generated and may contain mistakes; the official description above is the record.