chore(deps): update dependency brace-expansion@^1.1.7 to v2 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
brace-expansion@^1.1.7	1.1.16 → 2.1.4

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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
• https://github.com/juliangruber/brace-expansion/pull/129
• https://github.com/juliangruber/brace-expansion/pull/130
• https://github.com/juliangruber/brace-expansion/pull/136
• https://github.com/juliangruber/brace-expansion/commit/139d015104e71433ad52a41d19467c48ecbb2c7d
• https://github.com/juliangruber/brace-expansion/commit/cb4b9e47cc2ec777c14b2b4492fb431a56f6a031
• https://github.com/juliangruber/brace-expansion/commit/d13ff455a58b0d56704f0111e3c2a0b16ceb06eb
• https://github.com/advisories/GHSA-mh99-v99m-4gvg

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

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brace-expansion: DoS via unbounded intermediate arrays, bypassing the CVE-2026-14257 mitigation

CVE-2026-69152 / GHSA-rgw5-rvv9-x895

More information

Details

Summary

The maxLength mitigation added in 5.0.8 for GHSA-mh99-v99m-4gvg / CVE-2026-14257 is incomplete. It bounds the accumulator where results are combined, but not the intermediate arrays that feed it. A ~25 KB input still crashes the Node process with an uncatchable out-of-memory error, so try/catch around expand() does not help.

A second, related path in the same function lets a ~400 KB input block the event loop for over two minutes without ever exceeding the memory bound.

Details

maxLength was enforced in combine(), the single place output grows. Two arrays are built before combine() runs, and neither was bounded.

1. Comma alternatives accumulate without a running total (memory exhaustion)

Each alternative in {a,b,c,...} is expanded by its own recursive expand_() call, so each receives a full, independent maxLength allowance. The results were then concatenated into a single values array with no cumulative limit:

values = []
for (let j = 0; j < n.length; j++) {
  values.push.apply(values, expand_(n[j], max, maxLength, false))
}

acc = combine(acc, pre, values, max, maxLength, ...)

With A alternatives, values can reach A * maxLength characters before combine() gets a chance to truncate it. At the default maxLength of 4,000,000 and 400 alternatives, that is well past any default heap.

2. Padded sequences ignore maxLength while generating (CPU exhaustion)

expandSequence() was bounded by max (the result count) but never consulted maxLength. A padded sequence's element width follows the input, so {0...01..100000} with a wide pad generates max elements, each as wide as the input, only for combine() to discard all but a handful.

Memory stays flat here, because V8 represents the padded strings as cons-strings, which is likely why this path was not caught alongside the original issue. The cost is time: work proportional to max * width.

pad width	input bytes	results kept	time (5.0.8)	time (patched)
20,000	20 KB	199	~7.3 s	~20 ms
100,000	100 KB	39	~32 s	~20 ms
400,000	400 KB	9	~124 s	~18 ms

Output is byte-identical before and after the fix; only the wasted work is removed.

Proof of concept

Memory exhaustion, against 5.0.8:

import { expand } from 'brace-expansion'

const part = '{' + '0'.repeat(50) + '1..100000}'
const input = '{' + Array(400).fill(part).join(',') + '}'  // ~25 KB

try {
  expand(input)
} catch (e) {
  // never reached - the process is already dead
}

FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
Aborted

Event-loop stall, against 5.0.8:

import { expand } from 'brace-expansion'

// ~400 KB input, returns 9 results after roughly two minutes of blocking CPU
expand('{' + '0'.repeat(400_000) + '1..100000}')

Impact

Denial of service. Any application that passes attacker-controlled input to expand(), directly or transitively through a glob or pattern-matching library, can be remotely crashed or stalled. The out-of-memory variant terminates the process and cannot be handled with try/catch.

Applications already on 5.0.8 are affected: the 5.0.8 mitigation does not cover these paths.

Patches

Both intermediate arrays are now bounded as they are built, using the same max and maxLength limits already applied in combine():

• values tracks a running result count and character length while alternatives are appended, and stops once either bound is reached.
• expandSequence() accepts maxLength and stops generating once the sequence's own characters reach it.

As with the existing limits, output is truncated rather than allowed to grow without bound, which matches how max already behaves. The defaults sit well above any realistic expansion, so legitimate input is unaffected.

Workarounds

If upgrading is not immediately possible, avoid passing untrusted input to expand() or to glob brace patterns, or pass an explicitly small max and maxLength.

Note that a small maxLength alone was not sufficient on affected versions: it was applied per alternative rather than cumulatively, which is the root of the first issue above.

Credits

The memory-exhaustion bypass was reported by Alessio Della Libera, CEO & Co-founder at Numyra.

The sequence-generation issue was found while verifying that report.

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-rgw5-rvv9-x895
• https://github.com/juliangruber/brace-expansion/commit/139d015104e71433ad52a41d19467c48ecbb2c7d
• https://github.com/juliangruber/brace-expansion/commit/1e30c930238d7162802d88a94189182def178dac
• https://github.com/juliangruber/brace-expansion/commit/688a99eeaab02627c2b89ba8ba4821fecfa659cf
• https://github.com/juliangruber/brace-expansion/commit/cb4b9e47cc2ec777c14b2b4492fb431a56f6a031
• https://github.com/advisories/GHSA-rgw5-rvv9-x895

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

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Release Notes

juliangruber/brace-expansion (brace-expansion@^1.1.7)

v2.1.4

Compare Source

v2.1.3

Compare Source

v2.1.2

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v2.1.1

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• Backport v5.0.6 change to v2 (#​109) c3a817c

---

v2.1.0

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v2.0.3

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v2.0.2

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• pkg: publish on tag 2.x 14f1d91
• fmt ed7780a
• Fix potential ReDoS Vulnerability or Inefficient Regular Expression (#​65) 36603d5

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v2.0.1

Compare Source

v2.0.0

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v1.1.18

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v1.1.17

Compare Source

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Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

OpenSSF Scorecard

Package	Version	Score	Details
npm/brace-expansion	1.1.18	🟢 7.3	Details Check Score Reason Packaging ⚠️ -1 packaging workflow not detected Dangerous-Workflow 🟢 10 no dangerous workflow patterns detected Binary-Artifacts 🟢 10 no binaries found in the repo Token-Permissions 🟢 10 GitHub workflow tokens follow principle of least privilege Maintained 🟢 10 22 commit(s) and 5 issue activity found in the last 90 days -- score normalized to 10 Security-Policy 🟢 10 security policy file detected Code-Review 🟢 4 Found 7/16 approved changesets -- score normalized to 4 Pinned-Dependencies 🟢 10 all dependencies are pinned CII-Best-Practices ⚠️ 0 no effort to earn an OpenSSF best practices badge detected Fuzzing ⚠️ 0 project is not fuzzed License 🟢 9 license file detected Signed-Releases ⚠️ -1 no releases found Branch-Protection ⚠️ -1 internal error: error during branchesHandler.setup: internal error: some github tokens can't read classic branch protection rules: https://github.com/ossf/scorecard-action/blob/main/docs/authentication/fine-grained-auth-token.md SAST ⚠️ 0 SAST tool is not run on all commits -- score normalized to 0
npm/brace-expansion	2.1.4	🟢 7.3	Details Check Score Reason Packaging ⚠️ -1 packaging workflow not detected Dangerous-Workflow 🟢 10 no dangerous workflow patterns detected Binary-Artifacts 🟢 10 no binaries found in the repo Token-Permissions 🟢 10 GitHub workflow tokens follow principle of least privilege Maintained 🟢 10 22 commit(s) and 5 issue activity found in the last 90 days -- score normalized to 10 Security-Policy 🟢 10 security policy file detected Code-Review 🟢 4 Found 7/16 approved changesets -- score normalized to 4 Pinned-Dependencies 🟢 10 all dependencies are pinned CII-Best-Practices ⚠️ 0 no effort to earn an OpenSSF best practices badge detected Fuzzing ⚠️ 0 project is not fuzzed License 🟢 9 license file detected Signed-Releases ⚠️ -1 no releases found Branch-Protection ⚠️ -1 internal error: error during branchesHandler.setup: internal error: some github tokens can't read classic branch protection rules: https://github.com/ossf/scorecard-action/blob/main/docs/authentication/fine-grained-auth-token.md SAST ⚠️ 0 SAST tool is not run on all commits -- score normalized to 0

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