CVE-2026-87929
MaxSite CMS through 109.6 Authentication Bypass via Hardcoded Encryption Key
CVSS 4.0 9.3 CRITICALCVSS 3.1 9.8 CRITICALCheck source for fixed versionsKEV status unknown
cve-program · CVE-2026-87929
PublishedMaxSite CMS through 109.6 ships with a hardcoded session encryption key in application/config/config.php that is never changed during installation, allowing unauthenticated attackers to forge administrator session cookies. Attackers can mint a malicious ci_session cookie with administrator privileges by computing an HMAC-SHA1 using the publicly known encryption key, bypassing authentication checks in is_login() and mso_check_allow() functions.
Read the publisher's advisoryAffected versions, risk and source history
Related advisories and sources
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CVE-2026-87929 · CVE overview and exploitation status
cve-program · CVE-2026-87929
- https://github.com/maxsite/cms
- https://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md
- https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254
- https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/maxsite/common/core/init.php#L70-L96
- https://www.vulncheck.com/advisories/maxsite-cms-through-109.6-authentication-bypass-via-hardcoded-encryption-key
Related changes
Linked by CVE identifierNo related changes are available here.