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PatchSiren cyber security CVE debrief

CVE-2026-39918 givanz CVE debrief

CVE-2026-39918 is a critical vulnerability in Vvveb prior to version 1.0.8.1. The vulnerability is caused by a code injection issue in the installation endpoint where the subdir POST parameter is written unsanitized into the env.php configuration file without escaping or validation. This allows attackers to inject arbitrary PHP code by breaking out of the string context in the define statement, achieving unauthenticated remote code execution as the web server user. The vulnerability has a CVSS score of 9.2 and is considered critical.

Vendor
givanz
Product
Vvveb
CVSS
CRITICAL 9.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-20
Original CVE updated
2026-07-14
Advisory published
2026-04-20
Advisory updated
2026-07-14

Who should care

This vulnerability affects users of Vvveb prior to version 1.0.8.1. It is crucial for administrators and users of this software to take immediate action to mitigate the risk of unauthenticated remote code execution. Operators, platform administrators, and security teams should review the installation endpoint and env.php configuration file to ensure proper sanitization of user input and prevent code injection.

Technical summary

The CVE-2026-39918 vulnerability is caused by improper sanitization of user input in the installation endpoint of Vvveb. Specifically, the subdir POST parameter is written directly to the env.php configuration file without proper escaping or validation. This allows an attacker to inject malicious PHP code, potentially leading to unauthenticated remote code execution as the web server user. The vulnerability affects Vvveb prior to version 1.0.8.1 and has a CVSS score of 9.2.

Defensive priority

High

Recommended defensive actions

  • Update Vvveb to version 1.0.8.1 or later
  • Restrict access to the installation endpoint
  • Implement additional security measures such as web application firewalls and intrusion detection systems
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE-2026-39918 vulnerability was publicly disclosed on April 20, 2026, and has since been modified on July 14, 2026. The vulnerability has a CVSS score of 9.2 and is considered critical. Evidence of exploitation is limited, but defenders should verify the installation endpoint for Vvveb prior to version 1.0.8.1 and ensure proper sanitization of user input. Additional review of the env.php configuration file and define statements is necessary to prevent code injection.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-39918 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-39918

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-39918 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-39918

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.