# CVE-2026-17520: Newsletters < 4.17 - Unauthenticated API Access via Predictable API Key

> Unauthenticated attackers can predict the API key to perform privileged actions like managing subscribers and sending emails if the optional API is enabled.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Aug 2026
- **Updated:** 30 Aug 2026
- **Also known as:** GHSA-jf3w-mh76-5398

## What is CVE-2026-17520?

CVE-2026-17520 is a medium-severity vulnerability in Unknown Newsletters, published on 29 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Newsletters WordPress plugin before 4.17 does not generate its API key using a sufficiently random source, deriving it from a publicly known value, allowing unauthenticated attackers to compute the key and perform privileged actions such as adding and deleting subscribers and sending emails, when the optional API has been enabled.

Weakness: CWE-326 (Inadequate Encryption Strength)

## Which versions are affected by CVE-2026-17520?


## How do I fix CVE-2026-17520?

No fix has been published for CVE-2026-17520 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-17520 being exploited?

There is no known exploitation of CVE-2026-17520 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-17520 and fix it if it is affected.

What it is: CVE-2026-17520 is a medium-severity vulnerability in Unknown Newsletters, published on 29 Aug 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-2026-17520 in the wild and no public exploit code.

Affected product: Unknown Newsletters. 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-2026-17520/ (Markdown: https://insights.sbomify.com/CVE-2026-17520/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-17520
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-17520
- OSV: https://osv.dev/vulnerability/CVE-2026-17520

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-17520/
Summaries are generated and may contain mistakes; the official description above is the record.