# CVE-2026-16603: Content Protector (Passster) < 4.3.6 - Unauthenticated Category-Locked Content Disclosure via Core REST API

> Unauthenticated attackers can bypass category-based content protection to read full post content via the WordPress REST API.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:** 5 Aug 2026
- **Updated:** 5 Aug 2026
- **Also known as:** GHSA-w2h3-gqm7-9j89

## What is CVE-2026-16603?

CVE-2026-16603 is a high-severity missing authorization vulnerability in Unknown Passster, published on 5 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Passster  WordPress plugin before 4.3.6 does not enforce its category-based content protection on the WordPress REST API, allowing unauthenticated users to read the full content, title, and excerpt of category-locked posts through the core REST API.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-16603?


## How do I fix CVE-2026-16603?

No fix has been published for CVE-2026-16603 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-16603 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16603 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-16603 and fix it if it is affected.

What it is: CVE-2026-16603 is a high-severity missing authorization vulnerability in Unknown Passster, published on 5 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16603 exists.

Affected product: Unknown Passster. 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-2026-16603/ (Markdown: https://insights.sbomify.com/CVE-2026-16603/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-16603
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-16603
- OSV: https://osv.dev/vulnerability/CVE-2026-16603

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-16603/
Summaries are generated and may contain mistakes; the official description above is the record.