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High, CVSS 7.5amended

brace-expansion: DoS via uncontrolled recursion on nested brace groups causing stack exhaustion

CVE-2026-102278GHSA-qhr7-859c-m2p7

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (brace-expansion 5.0.11, 3.0.8, 2.1.6, 1.1.20), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm brace-expansion

    Affected
    >= 4.0.0, < 5.0.11>= 3.0.0, < 3.0.8>= 2.0.0, < 2.1.6< 1.1.20
    Fixed in
    3.0.8, 1.1.20, 5.0.11, 2.1.6

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-102278: 0.49% estimated exploitation activity in the next 30 days; percentile 42.25 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary expand() recurses once per level of brace nesting. Deeply nested input exhausts the native stack and crashes the process. This is distinct from CVE-2026-14257 / GHSA-mh99-v99m-4gvg, which made the tail iterative (recursion on m.post, driven by how many groups are chained). Nesting depth drives a different recursion that the tail fix never touched, so the documented constant-stack-depth guarantee only ever covered chained input, not nested input. It is also distinct from GHSA-6j4f-fj2g-mc7p, which fixed recursion in parseCommaParts(). Both payloads below still crash with that fix applied. Two recursion sites Comma members. Each alternative of a brace set is expanded by a recursive call, so nesting a set inside every alternative recurses once per level: Crashes at depth 3,907 - about 15.6 KB of input. Single set. A brace set whose body parses to a single part is expanded by a recursive call before being re-wrapped (x{{a,b}}y - x{a}y x{b}y), which recurses once per nesting…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-qhr7-859c-m2p7

  2. Revision 2 · amended ·

    Amended from osv record GHSA-qhr7-859c-m2p7

  3. Revision 1 · created ·

    Published from ghsa record GHSA-qhr7-859c-m2p7

Agent brief

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# Patch Next advisory brief: CVE-2026-102278

Advisory: brace-expansion: DoS via uncontrolled recursion on nested brace groups causing stack exhaustion
IDs: CVE-2026-102278, GHSA-qhr7-859c-m2p7
Record: https://patchnext.com/advisories/cve-2026-102278 (revision 3, source checked 26 Oct 2026, 13:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: brace-expansion 5.0.11, 3.0.8, 2.1.6, 1.1.20. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm brace-expansion: affected >= 4.0.0, < 5.0.11; >= 3.0.0, < 3.0.8; >= 2.0.0, < 2.1.6; < 1.1.20; fixed in 3.0.8, 1.1.20, 5.0.11, 2.1.6

## Suggested inspection (read-only)
- `npm ls brace-expansion --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on brace-expansion.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-qhr7-859c-m2p7 (GitHub-reviewed advisory GHSA-qhr7-859c-m2p7 lists affected ranges: npm brace-expansion >=4.0.0 =3.0.0 =2.0.0 =0 <1.1.20)
- Verified: https://osv.dev/vulnerability/GHSA-qhr7-859c-m2p7 (OSV record GHSA-qhr7-859c-m2p7 lists affected ranges: npm brace-expansion >=4.0.0 =3.0.0 =2.0.0 =0 <1.1.20 (fixed))

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