An argument parsing error in the kill utility of uutils coreutils incorrectly interprets kill -1 as a request to send the default signal (SIGTERM) to PID -1. Sending a signal to PID -1 causes the kernel to terminate all processes visible to the caller, potentially leading to a system crash or massive process termination. This differs from GNU coreutils, which correctly recognizes -1 as a signal number in this context and would instead report a missing PID argument.

Affected: crates.io: uu_kill

`kill -1` is incorrectly parsed as a positional `pid = -1`; combined with the default SIGTERM this calls `kill(-1, SIGTERM)`, signaling nearly every process the caller can see. GNU `kill` recognizes `-1`/`-9` as signals and reports "not enough arguments".

``` $ kill -1 # uutils: kill(-1, SIGTERM) -> mass termination / crash $ kill -1 # GNU: kill: not enough arguments ```

**Impact:** a user running `kill -1` mass-terminates processes, potentially crashing the system. Recommendation: parse `-N` as a signal number, and error with "not enough arguments" when no PID is given.

**Remediation:** Acknowledged by Canonical; fixed in commit cae94028.

--- _Reported by Zellic in the *uutils coreutils Program Security Assessment* (prepared for Canonical, Jan 20 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`. Finding 3.70. Credit: Zellic._

Affected: Ubuntu:24.04:LTS: rust-coreutils, Ubuntu:25.10: rust-coreutils

An argument parsing error in the kill utility of uutils coreutils incorrectly interprets kill -1 as a request to send the default signal (SIGTERM) to PID -1. Sending a signal to PID -1 causes the kernel to terminate all processes visible to the caller, potentially leading to a system crash or massive process termination. This differs from GNU coreutils, which correctly recognizes -1 as a signal number in this context and would instead report a missing PID argument.