CVE-2026-10721
Concrete CMS <9.5.2: unauthenticated PHP object injection via unserialize() in core components.
Is CVE-2026-10721 being exploited?
Not confirmed. CVE-2026-10721 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.14% probability of exploitation in the next 30 days.
How severe is CVE-2026-10721?
CVE-2026-10721 is rated High. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-10721?
Yes. A fix has been recorded for CVE-2026-10721. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-10721 affect?
CVE-2026-10721 affects Concrete CMS < 9.5.2. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-10721?
Upgrade to 9.5.2+; review serialized data handling.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can instantiate arbitrary PHP objects via crafted payload, risking code execution.
Immediate action required
- affected>= 5 and <= 9.5.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.