Grist is a spreadsheet software platform that uses Python as its formula language, allowing users to run complex computations within spreadsheets. To protect against malicious code execution, Grist provides sandboxing methods for running these Python formulas. One such method uses pyodide, a WebAssembly-based Python environment running on Node.js. However, pyodide on Node.js lacks effective sandboxing barriers, meaning that if a user opens a malicious spreadsheet document with the environment variable `GRIST_SANDBOX_FLAVOR` set to `pyodide`, the malicious code can escape the sandbox and execute arbitrary processes on the server hosting Grist. This vulnerability is classified under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), indicating injection risks that lead to code execution. The vulnerability affects all grist-core versions prior to 1.7.9. The vendor addressed the issue by changing the sandbox environment to run pyodide under deno, a secure runtime with better isolation capabilities. As an interim mitigation, users can switch the sandbox flavor to `gvisor`, a container-based sandboxing solution that provides stronger isolation. The CVSS v3.1 score is 9.1 (critical), reflecting the network attack vector, no privileges or user interaction required, and complete compromise of confidentiality, integrity, and availability. There are no known exploits in the wild yet, but the severity and ease of exploitation make this a high-risk vulnerability for any exposed deployments.

For European organizations, the impact of CVE-2026-24002 can be severe. Organizations using grist-core in server environments—especially those that allow uploading or sharing of spreadsheets from untrusted sources—are at risk of remote code execution attacks. Successful exploitation can lead to full system compromise, data theft, data manipulation, or service disruption. This is particularly critical for sectors handling sensitive or regulated data such as finance, healthcare, government, and education. The ability to execute arbitrary processes on the server can also facilitate lateral movement within networks, potentially affecting broader IT infrastructure. Given the criticality and the lack of required authentication or user interaction beyond opening a malicious document, the threat surface is broad. Additionally, organizations relying on grist-core for collaborative or cloud-based spreadsheet services may face increased exposure. The absence of known exploits in the wild does not reduce the urgency, as proof-of-concept exploits could emerge rapidly given the public disclosure.

European organizations should immediately upgrade all grist-core deployments to version 1.7.9 or later, where the vulnerability is fully patched by running pyodide under the deno runtime. If immediate upgrading is not feasible, administrators should configure the environment variable `GRIST_SANDBOX_FLAVOR` to `gvisor` to switch to a more secure sandboxing mechanism. Network-level protections should be applied to restrict access to Grist servers, limiting exposure to untrusted users and sources. Monitoring and logging should be enhanced to detect unusual process executions or sandbox escapes. Organizations should also review and restrict the types of spreadsheet documents accepted or shared, applying content scanning or sandboxing at the file upload stage. Regular vulnerability scanning and penetration testing focused on grist-core deployments can help identify residual risks. Finally, educating users about the risks of opening untrusted spreadsheets and maintaining strict access controls will reduce the likelihood of exploitation.