CVE-2026-70554
Unauthenticated PHP object injection in MaxSite CMS enabling remote code execution
Is CVE-2026-70554 being exploited?
Not confirmed. CVE-2026-70554 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 0.85% probability of exploitation in the next 30 days.
How severe is CVE-2026-70554?
CVE-2026-70554 is rated Critical with a CVSS score of 9.3. 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-2026-70554?
Not known from our data. No patch reference has been recorded for CVE-2026-70554, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-70554 affect?
CVE-2026-70554 affects MaxSite CMS, Websites running MaxSite CMS. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-70554?
Apply vendor patch when released; deploy WAF rules and block/inspect maxsite_comuser cookie
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated PHP object injection via maxsite_comuser cookie allows remote code execution by deserializing attacker-controlled objects (SoapClient/Imagick gadget chains possible).
Immediate action required
- affected>= 0.78 and <= 109.5
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.