CVE-2025-26996

Sign-up Sheets <= 2.3.0.1 - Unauthenticated Arbitrary Shortcode Execution

2025-04-15 00:00
Phan Trong Quan

Strategic Overview

Status
Patched in 2.3.1
Affected Plugin
Sign-up Sheets
Affected Version
<= 2.3.0.1
CVSS
6.5Medium
Weakness type
CWE-94 · Improper Control of Generation of Code ('Code Injection')
CVE
CVE-2025-26996
View all Sign-up Sheets vulnerabilities

At a glance

CVE-2025-26996 is a medium-severity Improper Control of Generation of Code ('Code Injection') vulnerability in the Sign-up Sheets WordPress plugin, affecting versions <= 2.3.0.1. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.3.1; sites on affected versions should update now. Disclosed April 2025, reported by Phan Trong Quan.

Vulnerability Overview

The The Sign-up Sheets plugin for WordPress is vulnerable to arbitrary shortcode execution in all versions up to, and including, 2.3.0.1. This is due to the software allowing users to execute an action that does not properly validate a value before running do_shortcode. This makes it possible for unauthenticated attackers to execute arbitrary shortcodes.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-94: Improper Control of Generation of Code ('Code Injection')

Reaching this weakness in Sign-up Sheets <= 2.3.0.1 takes no account at all. Code injection means input from a request reaches a language construct that evaluates code, so the attacker's text is executed rather than treated as data.

The injected code runs with the web server's privileges, giving the attacker the same access to the database and filesystem as WordPress itself. For Sign-up Sheets the fix is 2.3.1: builds <= 2.3.0.1 are affected, anything from 2.3.1 onward is not.

Remediation

Update to version 2.3.1, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Sign-up Sheets 2.3.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2025-26996https://www.wordfence.com/threat-intel/vulnerabilities/id/df268fbf-c784-429e-a77a-967aac529cbdhttps://nvd.nist.gov/vuln/detail/CVE-2025-26996

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C