Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-87930

CVE-2026-87930CRITICAL

MaxSite CMS through 109.6 PHP Object Injection via ci_session

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   P   N   N   H   H   H    9.2   .0061   47.1     —

AFFECTED
  Product      Versions  Fixed
  MaxSite CMS  0.78 –    —

TIMELINE
  Sep 9   Reserved by VulnCheck
  Sep 9   Published (CNA: VulnCheck)
  Sep 24  EXPLOIT PUBLISHED — CVE-2026-87930 (MaxSite CMS). Public exploit reference added.

CWE-502 · CNA: VulnCheck · CVSS v4.0 · 7 references · NVD status: Deferred

Description

MaxSite CMS through 109.6 passes the ci_session cookie to unserialize() without class restrictions, allowing unauthenticated attackers to inject PHP objects. Attackers can forge valid session cookies using the hardcoded encryption key to trigger magic methods and corrupt application state or achieve code execution if gadget classes exist.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
September 9, 2026	Reserved	Reserved by VulnCheck
September 9, 2026	Published	Published (CNA: VulnCheck)
September 24, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-87930 (MaxSite CMS). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
MaxSite	MaxSite CMS	—	0.78	—

Weaknesses

CWE-502

References (7)

https://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md [technical-description]
https://github.com/EviL0rd/maxsite-cve6/blob/main/2026.09.08-maxsite-cms-unsafe-unserialize-object-injection.md [exploit, technical-description]
https://github.com/maxsite/cms [product]
https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254 [technical-description]
https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L670-L680 [technical-description]
https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/system/libraries/Session.php#L740-L742 [technical-description]
https://www.vulncheck.com/advisories/maxsite-cms-through-109.6-php-object-injection-via-ci-session [third-party-advisory]

Authoritative record: CVE-2026-87930 at cve.org

Vendors: maxsite

Weaknesses: CWE-502

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-87930 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.