The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to 1.1.18, 2.1.4, 3.0.6, and 5.0.9, expand() does not apply maxLength while constructing comma-alternative intermediate arrays or padded sequences, allowing attacker-controlled input to exhaust memory or block the event loop. The fix for CVE-2026-14257 is bypassed by the vulnerability. This issue is fixed in versions 1.1.18, 2.1.4, 3.0.6, and 5.0.9.

The brace-expansion library generates arbitrary strings containing a common prefix and suffix. From 5.0.0 to before 5.0.6, the max option was being applied too late. When expanding a single large numeric range like {1..10000000}, the sequence generation loop generates all 10 million intermediate elements before the max limit is applied With max=10, the output is correctly limited to 10 items, but the process still allocates ~505 MB and spends ~800ms building the full intermediate array. This vulnerability is fixed in 5.0.6.

The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13, a brace pattern with a zero step value (e.g., `{1..2..0}`) causes the sequence generation loop to run indefinitely, making the process hang for seconds and allocate heaps of memory. Versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13 fix the issue. As a workaround, sanitize strings passed to `expand()` to ensure a step value of `0` is not used.