CVE-2026-81910: Improper Neutralization of Special Elements Used in a Template Engine

Concrete CMS 9 through 9.5.2 is vulnerable to Server-Side Template Injection SSTI in Theme Customizer via Unvalidated Style Values. Values submitted through the customizer color channels and other style properties handled by ColorStyle and sibling Style classes such as FontFamilyStyle and...

CVE-2026-81918: Improper Neutralization of Input During Web Page Generation

Concrete CMS below 9.5.3 is vulnerable to Stored XSS via the Date Format field in the Page Attribute Display block. A user with editpagecontents permissions could store a payload which executes in the browser of any visitor who viewed a page where the block was configured to display a date-type...

PT-2026-90051

Concrete CMS versions 9.0.0 to 9.5.2 is vulnerable to Stored XSS in Board Custom Slot dialog. The custom slot save template endpoint authorizes the request only against the target board instance canEditBoardContents and then persists the client-supplied selectedTemplateOptioncollection verbatim,...

CVE-2026-81913: URL Redirection to Untrusted Site

Concrete CMS versions 9.5.0 through 9.5.2 are vulnerable to Open Redirect via the rcURL parameter. An attacker can craft a single link on the site's own domain that sends a user to an arbitrary external site immediately after authentication, facilitating phishing and credential theft. The same...

PT-2026-90050

GetSimple CMS is a content management system CMS, and GetSimple CMS CE is the community edition of that CMS. A logic flaw in GetSimple CMS v3.4.0a and below and GetSimpleCMS-CE v3.3.22 and below allows unauthenticated attackers to create a new administrator account. The application features an...

CVE-2026-81916: Missing Authorization

Concrete CMS before 9.5.3 evaluated the authorization check for an Express entry submission against the entity of the posted form rather than the entity identified by the dashboard route. As a result, a user permitted to add entries to one Express object could create entries in a different Expres...

PT-2026-90149

Name of the Vulnerable Software and Affected Versions Concrete CMS versions prior to 9.5.3 Description Cross-Site Request Forgery CSRF exists in the Move Multiple Groups feature. The endpoint 'dashboard/users/groups/bulkupdate/confirm' allows moving selected group tree nodes without validating an...

CVE-2026-81917: Improper Neutralization of Input During Web Page Generation

Concrete CMS below 9.5.3 does not apply HTML output escaping to the file description and tags fields when rendering the Document Library block, so a user with permission to edit file properties could store a script payload that executed in the browser of any visitor to a page displaying the block...

CVE-2026-81905: Incorrect Authorization

Concrete CMS below 9.5.3 stores user validation hashes for multiple purposes email/registration validation, password reset, and persistent login in a single table with a type column, but the redemption path resolves a hash by value alone and does not verify its type. As a result, a hash issued fo...

CVE-2026-81906

Concrete CMS prior to version 9.5.3 is affected by an OAuth callback login flaw. The vulnerable component is the OAuth callback login path , which failed to verify whether an account was active or email-validated before establishing a session. As a result, a deactivated or unvalidated user with a...

CVE-2026-81906 [UNREVIEWED] OAuth Callback Login Bypasses Deactivated-Account Checks

Concrete CMS OAuth callback login path prior to version 9.5.3 did not check whether an account was active or email-validated before establishing a session. A deactivated or unvalidated user with an existing OAuth binding could complete authentication and receive a session that was fully...

CVE-2026-81906 [UNREVIEWED] OAuth Callback Login Bypasses Deactivated-Account Checks

Concrete CMS OAuth callback login path prior to version 9.5.3 did not check whether an account was active or email-validated before establishing a session. A deactivated or unvalidated user with an existing OAuth binding could complete authentication and receive a session that was fully...

CVE-2026-81906 [UNREVIEWED] OAuth Callback Login Bypasses Deactivated-Account Checks

Concrete CMS OAuth callback login path prior to version 9.5.3 did not check whether an account was active or email-validated before establishing a session. A deactivated or unvalidated user with an existing OAuth binding could complete authentication and receive a session that was fully...

CVE-2026-81905 Concrete CMS below 9.5.3 does not enforce validation-hash type on redemption, allowing a hash issued for one purpose to be redeemed for another.

Concrete CMS below 9.5.3 stores user validation hashes for multiple purposes email/registration validation, password reset, and persistent login in a single table with a type column, but the redemption path resolves a hash by value alone and does not verify its type. As a result, a hash issued fo...

CVE-2026-81905

Concrete CMS versions below 9.5.3 store user validation hashes (email/registration validation, password reset, persistent login) in a single table with a type column, but the redemption path resolves a hash by value alone without verifying its type . This allows a long-lived registration hash (60...

CVE-2026-81905 Concrete CMS below 9.5.3 does not enforce validation-hash type on redemption, allowing a hash issued for one purpose to be redeemed for another.

Concrete CMS below 9.5.3 stores user validation hashes for multiple purposes email/registration validation, password reset, and persistent login in a single table with a type column, but the redemption path resolves a hash by value alone and does not verify its type. As a result, a hash issued fo...

CVE-2026-81905 Concrete CMS below 9.5.3 does not enforce validation-hash type on redemption, allowing a hash issued for one purpose to be redeemed for another.

Concrete CMS below 9.5.3 stores user validation hashes for multiple purposes email/registration validation, password reset, and persistent login in a single table with a type column, but the redemption path resolves a hash by value alone and does not verify its type. As a result, a hash issued fo...

CVE-2026-18121

Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass (IDOR) in the Calendar block's frontend event dialog (/ccm/calendar/view_event/{bID}/{occurrence_id}). The controller loads the event occurrence from an attacker-supplied sequential identifier without verifying that the caller ...

CVE-2026-18121 Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass (IDOR) in the Calendar block's frontend event dialog (/ccm/calendar/view_event/{bID}/{occurrence_id}).

Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass IDOR because the frontend calendar lightbox endpoint /ccm/calendar/viewevent/bID/occurrenceid does not verify that the caller is permitted to view the calendar that owns the requested event occurrence. The controller loads the...

CVE-2026-18121 Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass (IDOR) in the Calendar block's frontend event dialog (/ccm/calendar/view_event/{bID}/{occurrence_id}).

Concrete CMS 9.5.2 and below is vulnerable to an authorization bypass IDOR because the frontend calendar lightbox endpoint /ccm/calendar/viewevent/bID/occurrenceid does not verify that the caller is permitted to view the calendar that owns the requested event occurrence. The controller loads the...