An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group. In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped. This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group. The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

MISP contains a cross-site request forgery (CSRF) vulnerability in the sharing group quick-edit functionality. The addOrg, removeOrg, addServer, and removeServer actions share the __initialiseSGQuickEdit() helper, where the HTTP method validation intended to restrict these operations to POST requests was commented out. As a result, these state-changing actions could be invoked using GET requests. An attacker could craft a URL targeting one of the affected actions and cause an authenticated MISP user with sufficient privileges to request it, for example through a malicious link or embedded web resource. Successful exploitation could modify the membership of a MISP sharing group without the victim intentionally performing the operation. Depending on the action performed, an attacker could add or remove organisations or servers from a sharing group, potentially granting unintended access to information distributed through that sharing group or disrupting legitimate information sharing. The patch restores HTTP method enforcement centrally in __initialiseSGQuickEdit() by calling allowMethod(['post']), ensuring that all four affected quick-edit operations require POST requests and are therefore subject to the application's normal protections for state-changing requests.

An incorrect authorization vulnerability in MISP allowed authenticated users to delete attributes from events despite lacking the required perm_modify or perm_modify_org permissions. The affected attribute deletion paths relied on organization membership checks performed by MispAttribute::deleteAttribute() but did not consistently enforce MISP's event modification authorization rules. Consequently, a user belonging to the organization associated with an event could potentially delete individual attributes or perform bulk attribute deletion even when their assigned role was not authorized to modify the event. This created an inconsistency between attribute editing and deletion: editing an attribute correctly used MISP's ACL::canModifyEvent() authorization logic, whereas the affected deletion operations could bypass these permission checks. An authenticated attacker with access to an affected MISP instance and membership in the organization owning an event could exploit this flaw to remove attributes from that event, potentially causing unauthorized modification or loss of threat intelligence data. The patch introduces a common authorization check for all affected deletion paths. Before deletion, MISP now resolves the associated events and verifies that the current user is authorized to modify each event using the same authorization mechanism used by normal event and attribute modification operations.

A cross-site request forgery (CSRF) vulnerability exists in MISP due to form-security and CSRF protections being disabled based on whether an incoming request was identified as a REST request. MISP's REST detection can be influenced by request properties such as the URL suffix or the HTTP Accept header. Because Accept: application/json can be supplied by a cross-origin page without requiring a CORS preflight, an attacker could cause a request originating from another website to be treated as REST traffic. MISP would consequently disable its normal form-security and CSRF validation even though the request was authenticated using the victim's existing browser session. An unauthenticated remote attacker could exploit this behavior by convincing an authenticated MISP user to visit or interact with a malicious web page. The attacker's page could then issue crafted requests to susceptible state-changing MISP endpoints using the victim's privileges. Depending on the permissions of the victim and the targeted endpoint, this could allow unauthorized modification, creation, publication, or removal of data and other state changes. The vulnerability originates from granting the form-security exemption based on _isRest() rather than on the authentication mechanism used by the request. The patch changes this behavior so that CSRF and form-security exemptions are granted only when the request actually carries a MISP API key. Session-authenticated REST-style requests remain subject to CSRF protection. The fix also introduces support for transmitting CSRF tokens through the X-CSRF-Token header for legitimate same-origin AJAX requests. Such a header cannot normally be attached by a cross-origin page without triggering a CORS preflight, preventing it from being used to reproduce the original attack.

A persistent unsafe URL injection vulnerability exists in the MISP dashboard ButtonWidget configuration. Dashboard widget URLs were validated only when the widget was rendered and were not validated when the configuration was saved. As a result, an authenticated user able to modify dashboard widget settings could persist arbitrary URL values, including URLs using the javascript: scheme, through either of the dashboard settings persistence paths. A malicious javascript: URL stored in a dashboard button could potentially result in client-side script execution in the MISP security context if the value reached a rendering or navigation path without the existing runtime validation. Such execution could allow an attacker to perform actions with the privileges of the affected user or access information available to their MISP session. The practical exploitability of this issue is reduced by the fact that MISP already applied URL validation at render time, which neutralized known malicious values before they were presented to the user. The vulnerability therefore represents a persistence-layer validation gap and a defense-in-depth weakness rather than evidence of a direct bypass of the existing rendering protection. The patch introduces a canonical url schema type and validates dashboard widget configuration before it is persisted through either settings save mechanism. ButtonWidget URLs must now be strings resolving to an absolute path on the current MISP instance or a full URL with the same origin. Values using javascript:, external origins, malformed URL forms, and non-string values are rejected at save time.

MISP contains an authorization flaw in the OnDemand correlation engine where correlations were calculated solely from matching attribute values without applying the distribution, sharing group, organization, or other access-control restrictions associated with the correlated attributes and events. As a result, an authenticated user could receive correlation results referring to attributes or events that the user was not authorized to access. The vulnerable correlation collection path did not take the requesting user into account. The patch changes the correlation collector to accept the current user and filters the resulting attribute identifiers through MISP's existing fetchAttributesSimple() authorization logic, which evaluates event-, attribute-, object-, distribution-, and sharing-group-level restrictions against the live data. The issue also affected paths relying on previously stored correlation data. Because the OnDemand engine does not maintain the stored correlation table, its denormalized access-control information could be stale. The patch therefore validates correlated attribute identifiers against the current ACLs before returning them and additionally applies normal event visibility conditions when retrieving related events. An authenticated low-privileged user could exploit this issue by querying or creating attributes that correlate with restricted MISP content, potentially learning information about otherwise inaccessible events or attributes.

MISP installation scripts generated an Apache HTTP virtual-host configuration containing an incorrectly formatted HTTP-to-HTTPS redirect: Redirect permanent / https://misp.example Apache’s Redirect directive appends any portion of the requested path that follows the matched prefix to the configured destination URL. Because the destination did not end with /, attacker-controlled path content was appended directly to the hostname rather than to its URL path. For example, a request resembling: http://misp.example/@attacker.example/ could result in a redirect resembling: https://misp.example@attacker.example/ Under standard URL parsing, misp.example is interpreted as user information and attacker.example as the destination host. An unauthenticated remote attacker could therefore construct a URL hosted under the legitimate MISP domain that redirects users to an attacker-controlled website. The vulnerability could be used for phishing, credential collection, or potentially disclosing sensitive query-string information preserved during the redirect. Exploitation requires a user to follow the crafted HTTP URL. The fix adds the missing trailing slash to the redirect destination, ensuring that appended request data remains part of the path on the configured MISP host. Existing installationsExisting MISP installations should review their Apache HTTP virtual-host configuration and ensure that the HTTPS redirect destination ends with a trailing slash: Redirect permanent / https://misp.example/ After updating the configuration, validate it with apachectl configtest and reload or restart Apache for the change to take effect