Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-42687 – Unauthenticated PHP Object Injection – EventPrime WordPress Plugin (≤ 4.3.2.1)

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-42687 is a high-severity unauthenticated PHP Object Injection vulnerability in the EventPrime – Events Calendar, Bookings and Tickets WordPress plugin, affecting all versions up to and including 4.3.2.1. The flaw stems from deserialization of untrusted input (CWE-502), enabling unauthenticated remote attackers to inject malicious PHP objects with no authentication or user interaction required. With a CVSS v3.1 score of 8.1 (HIGH) and full confidentiality, integrity, and availability impact, this vulnerability presents a significant risk to any WordPress installation running the affected plugin version.

Technical details

  • Root cause: The plugin deserializes user-supplied input without adequate validation, classified under CWE-502 (Deserialization of Untrusted Data).
  • Trigger conditions: An unauthenticated attacker can send a specially crafted HTTP request to a vulnerable EventPrime endpoint to inject a malicious PHP object.
  • Attack vector: Network-accessible; no authentication or user interaction is required. Attack complexity is rated High (AC:H), as successful exploitation depends on the presence of a suitable Property-Oriented Programming (POP) chain through an additional co-installed WordPress plugin or theme.
  • Impact: If a suitable POP chain is present on the target system via another installed plugin or theme, exploitation can lead to arbitrary file deletion, sensitive data exfiltration, or remote code execution.

Affected software

  • EventPrime – Events Calendar, Bookings and Tickets (WordPress plugin), all versions ≤ 4.3.2.1

Severity

CVSS v3.1 Base Score: 8.1 (HIGH)
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Mitigation and recommended actions

  • Immediate: Update the EventPrime plugin to version 4.3.2.2 or later, which contains the vendor-issued fix.
  • If immediate patching is not feasible, consider temporarily deactivating the EventPrime plugin and restricting public-facing access to WordPress plugin endpoints until the update can be applied.

IONIX Status

The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge