CVE-2026-54786
Description
A flaw was found in Wasmtime, a runtime for WebAssembly. Its native implementation of WASIp1, a system interface for WebAssembly, contains a resource leak in the fd_renumber function. A malicious guest program can repeatedly call this function, causing the host system to exhaust its file descriptors (system resources used to access files or other input/output sources) and other resources. This can lead to a Denial of Service (DoS), making the system unavailable.
Statement
This flaw is rated as Low impact. Wasmtime's WASIp1 implementation can leak file descriptors when renumbering, allowing a malicious guest program to exhaust host resources and cause a Denial of Service. This issue primarily affects Red Hat products that utilize Wasmtime with WASIp1 enabled and allow guest programs to acquire file descriptors.
Mitigation
To mitigate this issue, configure Wasmtime environments to deny guest programs the ability to acquire file descriptors, such as preventing file system access. This restriction limits the attack surface by preventing the `fd_renumber` function from leaking host resources. Consult product-specific documentation for instructions on configuring Wasmtime security policies to restrict file access. If the Wasmtime service is reloaded or restarted, ensure the configuration changes persist.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Other); DoS: Resource Consumption (Memory); DoS: Resource Consumption (CPU)
An attacker that can influence the allocation of resources that are not properly released could deplete the available resource pool and prevent all other processes from accessing the same type of resource. Frequently-affected resources include memory, CPU, disk space, power or battery, etc.
Frequently Asked Questions
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