# CVE-2026-4509: PbootCMS File Upload file.php incomplete blacklist

> Attackers can upload malicious files due to an incomplete blacklist in PbootCMS, potentially leading to remote code execution.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Mar 2026
- **Updated:** 24 Mar 2026
- **Also known as:** GHSA-w42h-9gvx-cgmj

## What is CVE-2026-4509?

CVE-2026-4509 is a medium-severity vulnerability in PbootCMS, published on 21 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security flaw has been discovered in PbootCMS up to 3.2.12. This affects an unknown function of the file core/function/file.php of the component File Upload. The manipulation of the argument black results in incomplete blacklist. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks.

Weakness: CWE-184 (Incomplete List of Disallowed Inputs), CWE-183 (Permissive List of Allowed Inputs)

## Which versions are affected by CVE-2026-4509?


## How do I fix CVE-2026-4509?

No fix has been published for CVE-2026-4509 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4509 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4509 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4509 and fix it if it is affected.

What it is: CVE-2026-4509 is a medium-severity vulnerability in PbootCMS, published on 21 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4509 exists.

Affected product: PbootCMS. 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-2026-4509/ (Markdown: https://insights.sbomify.com/CVE-2026-4509/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4509
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4509
- OSV: https://osv.dev/vulnerability/CVE-2026-4509

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4509/
Summaries are generated and may contain mistakes; the official description above is the record.