PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-39573 Select-Themes CVE debrief

CVE-2026-39573 is a high-severity vulnerability in the Mildhill theme, allowing unauthenticated PHP object injection. The vulnerability has a CVSS score of 8.1 and was published on June 17, 2026. The affected version is 1.5 or earlier. Users of the Mildhill theme should take immediate action to mitigate this vulnerability. The vulnerability allows attackers to inject malicious PHP objects, potentially leading to code execution. This vulnerability is considered high-risk and requires prompt attention.

Vendor
Select-Themes
Product
Mildhill
CVSS
HIGH 8.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-17
Original CVE updated
2026-06-17
Advisory published
2026-06-17
Advisory updated
2026-06-17

Who should care

Administrators and users of the Mildhill theme, particularly those using version 1.5 or earlier, should be aware of this vulnerability and take necessary precautions. This vulnerability can be exploited by unauthenticated attackers, making it a high-risk issue.

Technical summary

CVE-2026-39573 is an unauthenticated PHP object injection vulnerability in the Mildhill theme, version 1.5 or earlier. The vulnerability has a CVSS score of 8.1 and a CVSS vector of CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. The CWE associated with this vulnerability is CWE-502. The vulnerability allows attackers to inject malicious PHP objects, potentially leading to code execution.

Defensive priority

High

Recommended defensive actions

  • Update the Mildhill theme to the latest version.
  • Restrict access to the theme's files and directories.
  • Implement additional security measures, such as web application firewalls.
  • Monitor the theme's logs for suspicious activity.
  • Consider using a security plugin or service to detect and prevent attacks.
  • Review and update the theme's configuration and settings.
  • Limit the use of PHP object injection in the theme's code.

Evidence notes

The information provided is based on the CVE record and the NVD detail. The CVE record was published on June 17, 2026, and the NVD detail was last modified on June 17, 2026. The vulnerability was reported by [email protected].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-39573 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-39573

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

  • CVE-2026-39573 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-39573

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

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.