chore(deps): update dependency brace-expansion@>=5.0.0 <5.0.6 to >=5.0.8 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
brace-expansion@>=5.0.0 <5.0.6	[>=5.0.6 → >=5.0.8](https://renovatebot.com/diffs/npm/brace-expansion@>=5.0.0 <5.0.6/5.0.6/5.0.8)

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brace-expansion: DoS via exponential-time expansion of consecutive non-expanding {} groups

CVE-2026-13149 / GHSA-3jxr-9vmj-r5cp

More information

Details

Summary

brace-expansion's expand() exhibits exponential-time - O(2ⁿ) - behavior in the number of consecutive non-expanding {} groups. A short, all-ASCII input (~90 bytes/30 groups) blocks the calling thread for minutes; a slightly longer input hangs it effectively indefinitely. Because the dominant consumers run on Node's single-threaded event loop, one small input can fully stall a worker/process.

In expand_, post is computed unconditionally at the top of the function, before the early-return branches that don't use it:

const post = m.post.length ? expand_(m.post, max, false) : [''];   // always recurses
  ...
if (!isSequence && !isOptions) {
  if (m.post.match(/,(?!,).*\}/)) {
    str = m.pre + '{' + m.body + escClose + m.post;
    return expand_(str, max, true); // restart — `post` discarded
  }
  return [str];
}

For input like a{},{},…, the first {} is non-expanding, so control reaches the {a},b} rewrite branch - but expand_ has already recursed into post over the entire remaining tail, only to throw the result away.
Each level therefore spawns two recursive expansions over essentially the same remaining work: T(n) = 2·T(n−1) ⇒ O(2ⁿ).

The max option does not mitigate this: max only bounds the output-building loops; neither the post recursion nor the rewrite recursion consults it.

Measured on 5.0.6:

groups (n)	input bytes	time
20	60	130 ms
24	72	1.9 s
26	78	7.8 s
30 (PoC)	90	~2 min

Proof of concept

const { expand } = require('brace-expansion');
// 30 non-expanding groups, ~90 bytes — blocks for minutes:
expand('a{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{},{}');

Impact

Any application that passes attacker-influenced strings to brace-expansion.expand() - directly or transitively via minimatch/glob brace patterns - can be driven into a multi-minute-to-indefinite CPU hang by a tiny request, denying service on that thread/process.

Remediation

Upgrade to a patched release. The fix:

1. Defers computing post until after the early-return branches (and computes it locally in the $-suffix branch), so post is only expanded when a brace set actually expands and the value is used. This alone removes the exponential.
2. Converts the {a},b} rewrite from recursion to an in-function loop, so a long run of rewrites cannot grow the call stack.

Verified: the PoC drops from ~2 min to 0.55 ms, 5,000 groups complete in ~344 ms, and output is identical to 5.0.6 across a behavioral-equivalence suite (sequences, padding, $-prefix, a{},b}c, {},a}b, x{{a,b}}y, etc.). Post-fix complexity is ~O(n²) on this input class - acceptable for the security fix; a linear rewrite can be a non-urgent follow-up.

If immediate upgrade isn't possible, avoid passing untrusted input to expand() / glob brace patterns, or run such expansion under a timeout/worker.

Severity

• CVSS Score: 7.7 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/S:N/AU:Y/R:U/V:D/RE:M/U:Amber

References

• https://github.com/juliangruber/brace-expansion/security/advisories/GHSA-3jxr-9vmj-r5cp
• https://nvd.nist.gov/vuln/detail/CVE-2026-13149
• https://github.com/juliangruber/brace-expansion/pull/122
• https://github.com/juliangruber/brace-expansion/pull/123
• https://github.com/juliangruber/brace-expansion/commit/835d6be91201122d9adffb0c0c8c094189ace265
• https://github.com/juliangruber/brace-expansion/commit/c7e33ec13ac1a684c116720843ce24e208611754
• https://github.com/juliangruber/brace-expansion/commit/d74e63030c012e3b7ae81657b8d665619cd51b95
• https://github.com/juliangruber/brace-expansion
• https://github.com/juliangruber/brace-expansion/releases/tag/v1.1.16
• https://github.com/juliangruber/brace-expansion/releases/tag/v2.1.2
• https://github.com/juliangruber/brace-expansion/releases/tag/v5.0.7
• https://www.npmjs.com/package/brace-expansion

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

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brace-expansion: DoS via unbounded expansion length causing an out-of-memory process crash

CVE-2026-14257 / GHSA-mh99-v99m-4gvg

More information

Details

Summary

expand() bounds the number of results it produces (the max option,
100_000 by default) but not their length. By chaining many brace groups,
an attacker keeps the result count under max while making every result grow
with the number of groups. Building max long results — plus the intermediate
arrays combined at each brace group — exhausts memory and crashes the Node
process with an uncatchable out-of-memory error. try/catch around
expand() does not help: the fatal error terminates the process.

A ~7.5 KB input ('{a,b}'.repeat(1500)) is enough to crash a default Node
process.

Details

For N chained brace groups such as '{a,b}'.repeat(N):

• the result count is 2^N, immediately capped at max (100_000), so the
  max protection appears to hold, but
• each result is N characters long, so the total output size is
  max × N characters, which grows without bound in N.

expand_ combines each brace set with the fully-expanded tail:

const post = m.post.length ? expand_(m.post, max, false) : ['']
...
for (let j = 0; j < N.length; j++) {
  for (let k = 0; k < post.length && expansions.length < max; k++) {
    const expansion = pre + N[j] + post[k]   // grows one group longer per level
    ...
    expansions.push(expansion)
  }
}

The loop guard expansions.length < max limits how many strings are built, but
nothing limits how long they get. Each recursion level materializes another
array of up to max strings, one character longer than the level below, and —
because V8 represents pre + N[j] + post[k] as a cons-string (rope) that
references post[k] — those intermediate strings stay reachable through the
whole chain. Memory therefore scales with max × N.

Measured on 5.0.7 ('{a,b}'.repeat(N), default max):

groups (N)	input bytes	result count	peak RSS
20	100	100,000	~80 MB
50	250	100,000	~214 MB
100	500	100,000	~409 MB
300	1,500	100,000	~1,148 MB
1500	7,500	—	OOM crash

Proof of concept

const { expand } = require('brace-expansion')

// ~7.5 KB input — crashes the process with a fatal, uncatchable OOM:
//   FATAL ERROR: ... JavaScript heap out of memory
try {
  expand('{a,b}'.repeat(1500))
} catch (e) {
  // never reached — the process is already dead
}

Impact

Any application that passes attacker-influenced strings to
brace-expansion.expand() — directly, or transitively via minimatch / glob
brace patterns — can be crashed by a small request. Because the failure is a
fatal V8 out-of-memory error rather than a thrown exception, it cannot be caught
and it takes down the whole worker/process, denying service.

Remediation

Upgrade to a patched release. The fix bounds the total number of characters a
single expand() call may accumulate (EXPANSION_MAX_LENGTH, default
4_000_000, configurable via a new maxLength option), applied inside the
output-building loops so intermediate arrays are bounded too. Once the limit is
reached, output is truncated — consistent with how max already truncates —
instead of growing without bound. The limit sits well above any realistic
expansion (100,000 results hitting max measure ~1M characters), so legitimate
input is unaffected.

After the fix, '{a,b}'.repeat(1500) returns a bounded, truncated result in
~0.7 s using ~340 MB and never crashes, including under a constrained 512 MB
heap.

The fix bounds memory but the algorithm still rebuilds intermediate arrays at
each level (roughly O(N × maxLength) work on this input class). A streaming
rewrite that produces output in O(total output size) can be a non-urgent
follow-up.

If immediate upgrade isn't possible, avoid passing untrusted input to
expand() / glob brace patterns, or pass a small explicit max and
maxLength.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/juliangruber/brace-expansion/security/advisories/GHSA-mh99-v99m-4gvg
• https://nvd.nist.gov/vuln/detail/CVE-2026-14257
• https://github.com/juliangruber/brace-expansion/commit/a1bd33999ea75262c4749fff3bbb0d1372bd07b5
• https://github.com/juliangruber/brace-expansion
• https://www.npmjs.com/package/brace-expansion

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

juliangruber/brace-expansion (brace-expansion@>=5.0.0 <5.0.6)

v5.0.8

Compare Source

v5.0.7

Compare Source

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