What is CVE-2026-70554?

CVE-2026-70554 is a critical-severity vulnerability in Maxsite Cms, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-08-04.

How severe is CVE-2026-70554?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Maxsite Cms

CVE-2026-70554

MaxSite CMS contains a PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by passing attacker-controlled serialized data in the maxsite_comuser cookie directly to unserialize() without valida…

Vulnerability class: Insecure Deserialization

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Maxsite Cms — versions 0.78, 109.6

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

disclosure@vulncheck.com (product)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-70554?: CVE-2026-70554 is a critical-severity vulnerability in Maxsite Cms, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-08-04.
How severe is CVE-2026-70554?: Critical severity. CVSS v3 base score is 9.8 out of 10.