Skip to main content
CVE-2026-87929VulnerabilityPublished 09/09/2026Updated 09/24/2026

CVE-2026-87929: Use of Hard-coded Cryptographic Key in MaxSite MaxSite CMS

Affects MaxSite MaxSite CMSSource CVE Database V5

0

Not known to be exploited · CVSS 9.3 Critical.

Data as of 10/25/2026, 04:40:14 UTC

CVSS 4.0 base score
9.3Critical
How severe the flaw is on the 0–10 CVSS scale.
Exploitation

Not in CISA KEV, no exploitation reported

EPSS
0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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

What to do

Affected software

ProductAffectedFixed in
MaxSiteMaxSite CMSAffected
  • >=0.78 <=109.6
Fixed in–
GitHubMaxSite CMSpkg:github/MaxSite CMSOther threatsAffected
  • >=0.78 <=109.6
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until a fix is available, users should consider restricting access to the CMS or implementing additional authentication controls to mitigate risk.

Description

MaxSite 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.

Impact

The vulnerability enables unauthenticated attackers to gain administrator-level access to the MaxSite CMS by forging session cookies. This compromises the integrity and confidentiality of the CMS, potentially allowing full control over the affected system without any authentication.

References

Community reviews

Loading reviews…