Описание
brace-expansion: DoS via uncontrolled recursion in parseCommaParts causing stack exhaustion
Summary
parseCommaParts() can exhaust the native stack and crash the process. There are two distinct ways to trigger it, both reachable from a single untrusted pattern string.
This is the parsing-side counterpart to CVE-2026-14257 / GHSA-mh99-v99m-4gvg. That fix made expand_() iterative and documented a constant-stack-depth guarantee, but parseCommaParts() was left recursive, so the guarantee only held for one of the two parsing paths.
Vector 1 - unbounded recursion on post
parseCommaParts() recursed on the remainder of the string once per brace group:
A brace group containing many comma-separated groups drives one recursion level per group:
About 7,300 repetitions - roughly 29 KB of input - is enough on Node 24; roughly 6,300 (25 KB) on Node 18. The threshold is identical on every affected release line.
Vector 2 - push.apply with an unbounded array
Even with the recursion removed, parseCommaParts() spread whole arrays into an argument list:
Function.prototype.apply places one argument per element on the stack, so a single large array overflows it. This needs no recursion depth at all - the following reaches a recursion depth of exactly 1:
Threshold is about 124,300 repetitions (~249 KB). This vector was not part of the original report; it was found while verifying the fix. A patch that only de-recurses but keeps push.apply leaves a working denial of service behind.
Why max and maxLength do not help
Both crashes happen during parsing, before any expansion. The payloads produce one result per group, so output size grows linearly with input and is never the limiter. expand(payload, { max: 1, maxLength: 1 }) still overflows.
Impact
Any application that passes an untrusted string to expand() - directly, or through minimatch / glob where it is a user-supplied glob pattern - can be crashed. In Node, a RangeError that the application does not catch terminates the process, so a server that globs user input is exposed to remote unauthenticated denial of service.
minimatch's own MAX_PATTERN_LENGTH cap (65,536) does not help against vector 1: the overflow threshold sits well below it. Confirmed on minimatch 10.2.6 - a 64,003-byte pattern passes the length check and overflows both minimatch.braceExpand() and new minimatch.Minimatch().
This is an availability-only issue. No code execution and no data exposure.
Not a regression
5.0.8 and 5.0.9 overflow at the same repetition count, so the gap predates the recent advisories; those fixes simply did not reach it. Verified affected on 1.1.18, 2.1.4, 3.0.6, 5.0.8 and 5.0.9, all at an identical threshold.
Patch
parseCommaParts() is rewritten as a loop that carries the partial part across chunks, and every array append uses an element-by-element loop rather than push.apply. The redundant if (!str) return [''] guard is dropped - the loop returns [''] for the empty string on its own.
Equivalence of the old and new implementations was checked by differential testing: exhaustive over every string of {, }, ,, a up to length 7 plus 300,000 random inputs - 322,000 cases, zero mismatches.
Severity note
Scored 7.5 High under CVSS 3.1 for consistency with the other availability advisories on this package (GHSA-mh99-v99m-4gvg, GHSA-rgw5-rvv9-x895), which use the same vector. The reporter self-assessed 6.9 Medium under CVSS 4.0 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N).
Credit
Reported by baeseungwon1010, with a working proof of concept and a proposed patch. Vector 2 was identified during maintainer verification.
Ссылки
- https://github.com/juliangruber/brace-expansion/security/advisories/GHSA-6j4f-fj2g-mc7p
- https://nvd.nist.gov/vuln/detail/CVE-2026-102276
- https://github.com/juliangruber/brace-expansion/commit/0bcbfc0a5928c3073d48f42999d1ce4fc1c42fbc
- https://github.com/juliangruber/brace-expansion/commit/316359e6019c39b3254c8ba8e25dc586a480652c
- https://github.com/juliangruber/brace-expansion/commit/5171e681c0922b7ae8bfaf9a331e309107be6edc
- https://github.com/juliangruber/brace-expansion/commit/6735c94873ca570bcdd6a0690033bdd3126379d3
Пакеты
brace-expansion
>= 4.0.0, < 5.0.10
5.0.10
brace-expansion
>= 3.0.0, < 3.0.7
3.0.7
brace-expansion
>= 2.0.0, < 2.1.5
2.1.5
brace-expansion
< 1.1.19
1.1.19
Связанные уязвимости
The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to 1.1.19, 2.1.5, 3.0.7, and 5.0.10, crafted brace patterns can exhaust the native stack in parseCommaParts because parseCommaParts recursively processes the remainder once per brace group and uses push.apply to pass every element of a very large comma-part array as a function argument. Patterns containing many comma-separated brace groups trigger the recursive path, while the large array triggers the argument-array path without deep recursion. These paths cause recursive and argument-array native stack exhaustion before max or maxLength can limit output, potentially terminating the Node.js process in a process-terminating denial of service. This issue is fixed in versions 1.1.19, 2.1.5, 3.0.7, and 5.0.10.
The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to 1.1.19, 2.1.5, 3.0.7, and 5.0.10, crafted brace patterns can exhaust the native stack in parseCommaParts because parseCommaParts recursively processes the remainder once per brace group and uses push.apply to pass every element of a very large comma-part array as a function argument. Patterns containing many comma-separated brace groups trigger the recursive path, while the large array triggers the argument-array path without deep recursion. These paths cause recursive and argument-array native stack exhaustion before max or maxLength can limit output, potentially terminating the Node.js process in a process-terminating denial of service. This issue is fixed in versions 1.1.19, 2.1.5, 3.0.7, and 5.0.10.
The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to 1.1.19, 2.1.5, 3.0.7, and 5.0.10, crafted brace patterns can exhaust the native stack in parseCommaParts because parseCommaParts recursively processes the remainder once per brace group and uses push.apply to pass every element of a very large comma-part array as a function argument. Patterns containing many comma-separated brace groups trigger the recursive path, while the large array triggers the argument-array path without deep recursion. These paths cause recursive and argument-array native stack exhaustion before max or maxLength can limit output, potentially terminating the Node.js process in a process-terminating denial of service. This issue is fixed in versions 1.1.19, 2.1.5, 3.0.7, and 5.0.10.
brace-expansion: DoS via uncontrolled recursion in parseCommaParts causing stack exhaustion
The brace-expansion library generates arbitrary strings containing a c ...