PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-10721 Concrete CMS CVE debrief

CVE-2026-10721 is a high-severity vulnerability in Concrete CMS versions below 9.5.2. The vulnerability allows for PHP object injection via unserialize() calls in the Permission, Cache, and Search components. An unauthenticated attacker may trigger arbitrary PHP object instantiation if a malicious serialized payload has been placed in the database. The vulnerability has a CVSS score of 8.4 and is considered high severity.

Vendor
Concrete CMS
Product
Concrete CMS
CVSS
HIGH 8.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-10
Original CVE updated
2026-06-10
Advisory published
2026-06-10
Advisory updated
2026-06-10

Who should care

Users of Concrete CMS versions below 9.5.2 should apply the patch to prevent exploitation of this vulnerability.

Technical summary

The vulnerability is caused by insecure use of the unserialize() function in the Permission, Cache, and Search components of Concrete CMS. This allows an attacker to inject malicious PHP objects, potentially leading to arbitrary code execution.

Defensive priority

High

Recommended defensive actions

  • Apply the patch to upgrade Concrete CMS to version 9.5.2 or later.
  • Review the Concrete CMS documentation for additional guidance on securing the application.

Evidence notes

The vulnerability was reported by XananasX7.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-10721 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-10721

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

  • CVE-2026-10721 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-10721

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

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://documentation.concretecms.org/9-x/developers/introduction/version-history/952-release-notes

    ff5b8ace-8b95-4078-9743-eac1ca5451de

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.