CVE-2026-88405 in Univer
Summary
by MITRE • 09/22/2026
A remote code execution (RCE) vulnerability in the RemoteRegisterFunctionService function (/remote/remote-register-function.service.ts) of Univer v1.0.0-alpha.2 allows attackers to execute arbitrary code via a crafted payload.
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Analysis
by VulDB Data Team • 09/22/2026
The identified security flaw resides within the RemoteRegisterFunctionService component, specifically located at /remote/remote-register-function.service.ts in version 1.0.0-alpha.2 of the Univer software suite. This vulnerability represents a critical remote code execution (RCE) risk that stems from insufficient validation and sanitization of input data received by this service function. In modern web-based applications, particularly those involving collaborative editing or complex document manipulation like Univer, services handling remote interactions are often exposed to untrusted network inputs. When such functions fail to properly validate the structure, type, or content of incoming payloads before processing them, they create an attack surface that allows malicious actors to inject executable code into the application context. The specific nature of this flaw suggests a lack of strict schema enforcement or unsafe deserialization practices within the remote function registration mechanism, which is typically designed to dynamically load and execute custom functions provided by users or plugins.
From a technical perspective, the vulnerability likely exploits how the RemoteRegisterFunctionService parses and registers new functionality into the application runtime environment. If the service accepts arbitrary JavaScript objects or strings without rigorous type checking, an attacker can craft a payload that bypasses expected constraints. This could involve injecting malicious function definitions, overriding existing prototypes, or exploiting prototype pollution techniques to alter global state variables. Once executed within the browser sandbox of the victim user, this code operates with the same privileges as the legitimate application logic. The alpha status of version 1.0.0-alpha.2 indicates that the software is in an early development phase where security controls may not yet be fully hardened or thoroughly tested against adversarial inputs common in penetration testing scenarios.
The operational impact of successfully exploiting this vulnerability is severe, resulting in full remote code execution on the client side. An attacker who leverages this flaw can compromise the confidentiality, integrity, and availability of the user's session data. This includes stealing sensitive documents being edited, exfiltrating cookies or local storage tokens to hijack authenticated sessions, performing actions as the victim within the application interface, or using the compromised browser instance as a pivot point for further network attacks if cross-site scripting (XSS) chains are constructed. In enterprise environments where Univer is deployed for collaborative work, this could lead to widespread data breaches and significant reputational damage due to the trust users place in the platform's security posture.
This vulnerability aligns with CWE-94, Improper Control of Generation of Code ('Code Injection'), as it involves the injection of malicious code into a program that is then executed by the application. It also maps closely to MITRE ATT&CK technique T1059, Command and Scripting Interpreter, specifically within the context of client-side execution via JavaScript. The attack vector falls under Remote Code Execution (RCE) with Network access, indicating it can be exploited over a network without requiring prior authentication if the service endpoint is publicly accessible or if session validation is bypassed.
To mitigate this risk, immediate remediation should focus on implementing strict input validation and output encoding within the RemoteRegisterFunctionService. Developers must enforce schema-based validation for all incoming payloads to ensure that only expected data types and structures are processed. It is crucial to avoid using unsafe methods such as eval() or Function constructors with user-supplied strings unless absolutely necessary, in which case a robust allowlist of permitted functions should be maintained. Additionally, enabling Content Security Policy (CSP) headers can help restrict the sources from which scripts can be loaded and executed, thereby limiting the blast radius even if an injection attempt occurs. Upgrading to a patched version where these input sanitization controls are rigorously applied is the most effective long-term solution for organizations relying on this software stack.