CVE-2023-27431

Big Store <= 1.9.3 - Cross-Site Request Forgery to Arbitrary Plugin Activation

2023-03-05 00:00

Strategic Overview

Status: Patched in 1.9.4
Affected Theme: Big Store
Affected Version: <= 1.9.3
CVSS: 4.3Medium
Weakness type: CWE-352 · Cross-Site Request Forgery (CSRF)
CVE: CVE-2023-27431

At a glance

CVE-2023-27431 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Big Store WordPress theme, affecting versions <= 1.9.3. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.9.4; sites on affected versions should update now. Disclosed March 2023, reported by Dave Jong.

Vulnerability Overview

The Big Store plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.9.3. This is due to missing or incorrect nonce validation on the default_home and th_activeplugin functions. This makes it possible for unauthenticated attackers to activate arbitrary plugins via a forged request, granted they can trick a site administrator into performing an action such as clicking on a link.

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.

CWE-352: Cross-Site Request Forgery (CSRF)

Reaching this weakness in Big Store <= 1.9.3 takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.

An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. For Big Store the fix is 1.9.4: builds <= 1.9.3 are affected, anything from 1.9.4 onward is not.

Remediation

Update to version 1.9.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Big Store: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Big Store 1.9.4 closes this, and updating the theme is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-27431 https://www.wordfence.com/threat-intel/vulnerabilities/id/a1859dca-d771-470c-ae4a-48246977212c https://nvd.nist.gov/vuln/detail/CVE-2023-27431

Related records

Other vulnerabilities in Big Store

4.3CVE-2025-30881: Big Store <= 2.0.8 Missing AuthorizationCVE-2025-30881

CVSS Vector

4.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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