External risk intelligence

Moderno Theme Unauthenticated PHP Object Injection Vulnerability.

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-49108

An unauthenticated PHP Object Injection vulnerability exists in the Moderno web theme. This flaw allows remote attackers to execute arbitrary code, potentially leading to a full system compromise if the theme is reachable. Understanding the presence and reachability of this theme is important for assessing risk.

4Halo Surface Signal

Deserialization

External exposure likelihood

Halo Surface Signal score for CVE-2026-49108

The vulnerability affects a web theme, which is commonly deployed as part of public-facing web applications. Such themes are accessible via the internet by default when installed on a web server, making the vulnerable code path reachable by external users.

PCI scan relevance

PCI Relevance for CVE-2026-49108

Yes

CVE-2026-49108 — Halo PCI Relevance: Yes. Under typical PCI ASV external scan criteria, this issue may be flagged for scan prioritization.

PHP Object Injection in Moderno versions prior to 1.43 allows unauthenticated attackers to execute code or perform SQL injection. These types of vulnerabilities are a critical risk and could cause a PCI ASV scan to fail.

Scan-prioritization guidance only—not a PCI DSS certification or ASV attestation.

CVSS vector

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

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a critical vulnerability in a widely used web theme that allows unauthenticated attackers to inject malicious code remotely. The issue could potentially lead to a complete compromise of affected systems if the theme is in use. The primary concern at this stage is to confirm if this specific theme is deployed within our environment and to what extent.

  • Unauthenticated code injection in a web theme.
  • Critical flaw can allow full system compromise.
  • Confirm relevance and exposure.

Attack Path

How an attacker could exploit the issue

An attacker can exploit this vulnerability by sending specially crafted data over the network to a web application using the affected theme. This data can trigger a flaw in how the application handles serialized PHP objects, leading to the execution of arbitrary code.

  • No authentication required.
  • Triggered by unsanitized input.
  • Remote code execution risk.

Live Threat

Current exploitation, exposure, and threat context

This unauthenticated PHP Object Injection vulnerability in Moderno could allow an attacker to remotely execute arbitrary code on the server when supported by the advisory's described conditions. This could lead to a complete compromise of the web application and its underlying server.

  • Server-side code execution.
  • Remote unauthenticated code injection.
  • Complete server compromise.

Operational Fix

Recommended remediation, mitigation, and detection steps

Real-world ownership for this critical vulnerability likely falls to the application or platform team responsible for the Moderno theme, with support from the security team for exposure assessment. The initial practical step is to identify all instances of the affected theme, confirm their reachability and business criticality, and then assign an accountable owner for remediation planning.

  • Theme owners should manage the issue.
  • Verify theme reachability and criticality first.
  • Plan remediation or risk reduction.

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Moderno theme?

Moderno is a software theme designed for web applications. It serves as a visual and functional framework that dictates how a site presents content and interacts with visitors. Developers and administrators install it to manage the user interface, but like any web component, it processes incoming data from network requests. This vulnerability highlights the importance of keeping such application-layer extensions updated to ensure the security of the underlying server environment.

What does PHP object injection mean for CVE-2026-49108?

This vulnerability involves a weakness known as CWE-502, where the application improperly processes serialized data. When the software unserializes untrusted input, an attacker can inject malicious objects into the application memory. Because of how PHP handles these objects, this process can lead to the execution of arbitrary code, allowing the attacker to manipulate the server's behavior or gain unauthorized control over the application.

How do attackers trigger this vulnerability?

An attacker triggers this flaw by sending specially crafted, unsanitized data over the network to the web application. Because the vulnerability allows for unauthenticated access, the attacker does not need a valid user account or login credentials to initiate the attack. The code injection is not triggered by standard site navigation or routine user interactions, but rather by deliberate, malicious inputs designed to exploit the theme's handling of serialized data.

Is my site at risk if I use Moderno?

According to Halo Surface Signal, this vulnerability is particularly relevant because web themes are typically deployed on public-facing applications. Since the code path is reachable via the internet by default, the potential for unauthorized external access is high. If your application using Moderno is connected to the internet, it should be considered a priority for assessment, as the flaw is accessible to anyone who can reach the server over the network.

What is the first step to address this CVE?

The immediate priority is to identify where the Moderno theme is deployed across your infrastructure. Determine which applications are running versions older than 1.43 and evaluate their reachability. Once you have a complete inventory, coordinate with the teams responsible for those applications to plan for updates or necessary risk mitigation, ensuring that the theme is brought to a secure, supported version.

References

Sources and related resources

Primary sources: NVD, CVE.org.

NVDPublished