Executive brief
BusyBox is a widely used software suite that provides essential command-line tools for embedded systems and Linux devices. A flaw in its command shell component allows an attacker to crash the system or cause a service outage by providing specially crafted input that triggers an infinite loop or excessive memory usage. This could lead to a denial of service, impacting the availability of connected devices or industrial equipment.
Technical details
A vulnerability exists in the ash shell component of BusyBox v1.38.0. The root cause is a lack of recursion depth limiting in the evalfun() function within shell/ash.c. An attacker can trigger this by supplying crafted input that causes recursive shell function calls, leading to stack exhaustion or a heap-related crash (reported as a heap overflow in the CVE description). A patch has been proposed to implement a MAX_ASH_FUNC_DEPTH limit of 1000 to prevent this exhaustion. The attack vector depends on how the shell processes external input; if the shell executes user-supplied scripts or commands, it can be exploited locally or remotely.
Affected products
- BusyBox BusyBox 1.38.0
Timeline
- 2026-06-16: patched: Patch proposed on BusyBox mailing list to limit recursion depth
- 2026-07-15: disclosed: CVE published to NVD