Custom Block Builder Plugin up to 4.2.0 on WordPress LazyBlocks_Blocks code injection

Summaryinfo

A vulnerability has been found in Custom Block Builder Plugin up to 4.2.0 on WordPress and classified as critical. Affected by this vulnerability is the function LazyBlocks_Blocks. Performing a manipulation results in Remote Privilege Escalation. This vulnerability is identified as CVE-2026-1560. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as critical has been found in Custom Block Builder Plugin up to 4.2.0 on WordPress. This affects the function LazyBlocks_Blocks. The manipulation with an unknown input leads to a remote privilege escalation vulnerability. CWE is classifying the issue as CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at wordfence.com. This vulnerability is uniquely identified as CVE-2026-1560. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/12/2026). The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• WordPress Plugin

Name

• Custom Block Builder Plugin

Version

• 4.0
• 4.1
• 4.2.0

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CPE 2.2info

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