Vitest releases prior to 3.2.7, 4.1.10, and 5.0.0‑beta.6 allow Browser Mode provider commands such as upload, takeScreenshot, screenshotMatcher, stopChunkTrace, deleteTracing, and annotateTraces to accept arbitrary browser‐supplied file paths. This bypasses the allowWrite permission gate and does not constrain paths to the project root, giving a client that can reach the Browser Mode API the ability to read any local files, create or overwrite images and trace files, or delete files accessible to the Vitest process even when allowWrite is false. The effect is potential data exfiltration, tampering, and sabotage of test artifacts, representing a significant confidentiality, integrity, and availability impact.

All Vitest installations from the vitest-dev vendor running a version older than 3.2.7, 4.1.10, or 5.0.0‑beta.6 are vulnerable. The issue is present in the vitest framework, a JavaScript testing library built on Vite, affecting environments that expose its Browser Mode API to untrusted clients.

With a CVSS score of 9.4 the vulnerability is classified as critical. No EPSS value is available, but the lack of any mitigations and the high severity indicate a strong risk that attackers can exploit it. The attack vector is inferred to be remote; any system component able to call the Browser Mode API can trigger the file‑access functions, thus overriding permission controls. The vulnerability is not listed in the CISA KEV catalog, yet the potential for arbitrary file manipulation renders it highly exploitable in practice.