Vulnerability · Published Jun 10, 2026 · Assigned by ConcreteCMS

CVE-2026-10721Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the in Permission, Cache, and Search components

High 8.4

In plain English

A high-severity unsafe deserialization in Concrete CMS from Concrete CMS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.4High

Exploit odds (30 days)0.1%top 96.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the in 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. Thanks XananasX7 for reporting.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	concrete5/concrete5	9.5.2	GHSA-g82f-9pw7-773w

Affected products (as reported)

Vendor	Product	Versions
Concrete CMS	Concrete CMS	5 – through 9.5.1

Weakness: CWE-502 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References

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