CVE-2026-39425
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk8th percentile - higher than 8% of all known CVEs
Summary
MaxKB versions 2.7.1 and below contain a Stored Cross-Site Scripting (XSS) vulnerability that allows authenticated users to inject arbitrary HTML and JavaScript into the Application prologue (Opening Remarks) field by wrapping malicious payloads in <html_rander> tags. The backend fails to sanitize or encode HTML entities in the prologue field, and the frontend renders this content using an innerHTML-equivalent mechanism, enabling persistent DOM-based Stored XSS against any visitor who opens the affected chatbot interface. The issue has been fixed in version 2.8.0.
Risk Assessment
Session hijacking, unauthorized actions performed on behalf of victims (such as deleting workspaces or applications), and sensitive data exposure may occur. Any visitor to the infected interface is at risk.
Recommendation
Update MaxKB to version 2.8.0 or later. Until patched, restrict access to application creation and editing, and review prologue fields for suspicious content.
Other vulnerabilities in MaxKB
See all- CVE-2026-79916Critical
MaxKB is an open-source AI assistant for enterprise. Prior to 2.10.5-lts, authenticated workspace members can inject control characters into AWS Bedrock access_key_id and secret_access_key fields that _update_aws_credentials writes to /root/.aws/credentials without safe parsing. An attacker can append a new AWS profile containing credential_process, then select that profile during a later model-validation request so botocore executes an attacker-controlled command as root.
- CVE-2026-77521Critical
MaxKB is an open-source AI assistant for enterprise. Prior to version 2.10.5-lts, assistants with a tool, MCP tool, skill, or sub-application use SandboxShellBackend, which exposes an execute shell tool without excluding it and omits execute from interrupt_on, so human approval is not required. Untrusted chat or ingested content can therefore cause command execution; source deployments with MAXKB_SANDBOX disabled run commands directly as the application user, while the official root container's string-based gosu wrapper allowed shell metacharacters to execute outside the intended sandbox.
- CVE-2026-79919Medium
Prior to version 2.10.6-lts, function-library code running under the LD_PRELOAD sandbox can invoke ctypes.CDLL from an importlib.abc.MetaPathFinder callback so the dlopen call-stack heuristic sees a Python import frame, then use unhooked dlsym with RTLD_NEXT to resolve glibc's real syscall and bypass the sandbox syscall blacklist.
- CVE-2026-79918Medium
Prior to version 2.10.6-lts, the ToolExecutor LD_PRELOAD sandbox hooks execve, execvpe, and execveat to prevent subprocess creation but does not hook fexecve. An authenticated attacker able to execute tool code can call fexecve to start a process outside the sandbox's intended subprocess policy.
- CVE-2026-79917Medium
In MaxKB versions 2.7.0 through 2.10.4-lts, the POST /chat/api/{application_id}/chat/{chat_id}/share_chat endpoint verifies only that a conversation exists but does not verify it belongs to the authenticated chat_user_id or the application bound to the caller's token. An attacker with any chat token and a known victim chat_id can create a public ChatShareLink exposing the victim's conversation and PublicFileAccess state making associated files retrievable without credentials, with no revoke path.
- CVE-2026-77525Medium
In MaxKB 2.10.2-lts and earlier, management chat-record routes authorize the path application_id but load records using global chat_id and chat_record_id values without confirming the chat belongs to the authorized application. A normal user in the same workspace who knows the chat_id of a persisted record for a victim's published application can read victim chat records and copy victim answers via add_knowledge.
- CVE-2026-77523High
MaxKB, an open-source AI assistant for enterprise, in version 2.10.3-lts and earlier, has a vulnerability in the model parameter form route. An authenticated user with model read permission in an attacker-controlled workspace can read or overwrite the victim's model_params_form in another workspace using a known model_id, without including workspace_id in the query.
- CVE-2026-77522Medium
In MaxKB 2.10.3-lts and earlier, the knowledge web-document import and synchronization crawler passes an authenticated user's URL to Fork.fork, which calls requests.get with verify=False and without restricting schemes, loopback, link-local, private, or reserved addresses. The response body becomes imported document content, allowing a low-privileged user to read cloud metadata or internal HTTP services through the MaxKB server.
- CVE-2026-77520Medium
In MaxKB 2.10.2-lts and earlier, a normal user in the same workspace can obtain another user's application_id from the homepage application question-ranking endpoint when the victim's published application has ranking activity in the selected date range. An attacker who can create and publish workflow applications can place the disclosed identifier in a workflow node, trigger it, receive victim application output, and create durable application_chat records under the victim application.
- CVE-2026-77519Medium
In MaxKB 2.10.2-lts and earlier, the /chat/api/mcp authentication path looks up an ApplicationApiKey using only its secret and active status, without enforcing the is_permanent and expire_time checks used by the standard chat API. A previously valid, non-permanent application key that remains active after expiration can initialize the MCP endpoint, list tool metadata, invoke tools/call, and create durable application_chat state.
Original NVD description (English source)
MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a Stored Cross-Site Scripting (XSS) vulnerability that allows authenticated users to inject arbitrary HTML and JavaScript into the Application prologue (Opening Remarks) field by wrapping malicious payloads in <html_rander> tags. The backend fails to sanitize or encode HTML entities in the prologue field when applications are created or updated via the /admin/api/workspace/{workspace_id}/application endpoint, storing the raw payload directly in the database. The frontend then renders this content using an innerHTML-equivalent mechanism, trusting <html_rander>-wrapped content to be safe, which enables persistent DOM-based Stored XSS execution against any visitor who opens the affected chatbot interface. Exploitation can lead to session hijacking, unauthorized actions performed on behalf of victims (such as deleting workspaces or applications), and sensitive data exposure. This issue has been fixed in version 2.8.0.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

