The entr utility contains a heap-based buffer overflow in its run_utility() function. The function allocates a fixed-size heap buffer using malloc(ARG_MAX) and copies command-line arguments into it. It advances the destination pointer based on the return value of strlcpy(), which returns the total length of the source string rather than the number of bytes written. When the buffer is exactly filled, the remaining size underflows as an unsigned size_t, causing subsequent copies to write out of bounds. This can be triggered by supplying command-line arguments whose combined length fills the buffer or via the /_ substitution feature that expands a short token into a longer pathname at runtime. A local attacker can exploit this to cause memory corruption, process abort, and denial of service. The issue was fixed in commit 2467fe0.

Exploitation of this vulnerability allows a local attacker to cause memory corruption, which can lead to process abort and denial of service. There is no indication of privilege escalation or remote exploitation in the provided data.

A fix for this vulnerability is available as it was resolved in commit 2467fe0. Users should update entr to a version that includes this fix. Since no official patch version or advisory is provided, check the vendor repository or source for the fixed commit to apply the update.