How severe is CVE-2026-10721?

CVE-2026-10721 has a CVSS 4.0 base score of 8.4, rated high severity.

Is CVE-2026-10721 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-10721?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-10721 have an EU (EUVD) identifier?

Yes. CVE-2026-10721 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35994.

When was CVE-2026-10721 published?

CVE-2026-10721 was published on 2026-06-10 and last updated on 2026-06-17.

CVE-2026-10721

CVE-2026-10721 is a high-severity vulnerability with a CVSS 4.0 base score of 8.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: High (CVSS 4.0 base score 8.4)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35994
Weakness: CWE-502
Published: 2026-06-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-10721?: 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.
How severe is CVE-2026-10721?: CVE-2026-10721 has a CVSS 4.0 base score of 8.4, rated high severity.
Is CVE-2026-10721 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-10721?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-10721 have an EU (EUVD) identifier?: Yes. CVE-2026-10721 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35994.
When was CVE-2026-10721 published?: CVE-2026-10721 was published on 2026-06-10 and last updated on 2026-06-17.

References

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

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