# CVE-2026-1560: Custom Block Builder – Lazy Blocks <= 4.2.0 - Authenticated (Contributor+) Remote Code Execution

> Authenticated attackers with Contributor access can execute arbitrary code on the server via the Lazy Blocks plugin.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 11 Feb 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-3h85-7292-2f8x

## What is CVE-2026-1560?

CVE-2026-1560 is a high-severity code injection vulnerability in nko Custom Block Builder – Lazy Blocks, published on 11 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The Custom Block Builder – Lazy Blocks plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 4.2.0 via multiple functions in the 'LazyBlocks_Blocks' class. This makes it possible for authenticated attackers, with Contributor-level access and above, to execute code on the server.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-1560?


## How do I fix CVE-2026-1560?

No fix has been published for CVE-2026-1560 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-1560 being exploited?

There is no known exploitation of CVE-2026-1560 in the wild and no public exploit code.

Public exploit code:

- https://github.com/Z3YR0xX/CVE-2026-1560-Authenticated-Remote-Code-Execution-in-Lazy-Blocks-4.2.0 (github_poc): https://github.com/Z3YR0xX/CVE-2026-1560-Authenticated-Remote-Code-Execution-in-Lazy-Blocks-4.2.0

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-1560 and fix it if it is affected.

What it is: CVE-2026-1560 is a high-severity code injection vulnerability in nko Custom Block Builder – Lazy Blocks, published on 11 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-1560 in the wild and no public exploit code.

Affected product: nko Custom Block Builder – Lazy Blocks. 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-2026-1560/ (Markdown: https://insights.sbomify.com/CVE-2026-1560/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-1560
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-1560
- OSV: https://osv.dev/vulnerability/CVE-2026-1560

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-1560/
Summaries are generated and may contain mistakes; the official description above is the record.