CVE-2026-87929: MaxSite MaxSite CMS

MaxSite CMS through 109.6 Authentication Bypass via Hardcoded Encryption Key

CVSS 9.3 CriticalCriticalEPSS 0.0053 · 44th percentile

Critical, because:

CVSS score 9.3: 9.0 or more.

Published by the CVE Program (CNA: VulnCheck) at 9 Sept 2026, 16:45 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
MaxSite	MaxSite CMS pkg:github/maxsite/cms	affected 0.78 to 109.6, inclusive custom Other versions: unaffected

Identifiers

CVE-2026-87929

CNA

VulnCheck

Weakness (CWE)

CWE-321

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
9.3	Critical	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	CNA (VulnCheck)Used for this record
9.8	Critical	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0053, the 44th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 9 Sept 2026. New records show when each source confirmed them.

Sources

References from the CNA

github.com/maxsite/cms product
github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254 technical-description
github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/maxsite/common/core/init.php#L70-L96 technical-description
www.vulncheck.com/advisories/maxsite-cms-through-109.6-authentication-bypass-via-hardcoded-encryption-key third-party-advisory
github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md exploittechnical-description

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.