CyberSecBulletin
CVE-2026-87927NVD status: Deferred

MaxSite CMS: Improper Control of Filename for Include/Require Statement in PHP Program

Published Updated By the CyberSecBulletin desk

CVE-2026-87927 is a high-severity improper control of filename for include/require statement in PHP program vulnerability in MaxSite CMS from MaxSite, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected MaxSite CMS versions: 0.78 through 109.6. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.59% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of MaxSite CMS you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MaxSiteMaxSite CMS0.78 through 109.6Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
LowSome restricted data can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N. Scored by CNA (vulncheck.com).

Scoring systemScoreSeverityScored by
CVSS 4.08.8HighCNA (vulncheck.com)
CVSS 3.18.2HighCNA (vulncheck.com)

Official description

MaxSite CMS through 109.6 contains a local file inclusion vulnerability in the ajax and require-maxsite dispatchers that allows unauthenticated attackers to execute privileged handler files by supplying base64-encoded path traversal sequences. Attackers can bypass path validation checks and execute admin-gated handler actions without authentication to access sensitive functionality.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Control of Filename for Include/Require Statement in PHP Program

The PHP application receives input from an upstream component, but it does not restrict or incorrectly restricts the input before its usage in require, include, or similar functions.

How developers prevent this class of flaw

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
  • When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

More Improper Control of Filename for Include/Require Statement in PHP Program vulnerabilities (CWE-98)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).

References

Other vulnerabilities in MaxSite CMS

All MaxSite CMS vulnerabilities

Recent Improper Control of Filename for Include/Require Statement in PHP Program vulnerabilities

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