Quick answers
- Is CVE-2026-14257 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-14257 being exploited in the wild.
- How severe is CVE-2026-14257?
- High severity, with a CVSS score of 7.5, published 23 July 2026.
- Which products and versions are affected?
- brace-expansion (npm) <= 5.0.7, SEMVER:introduced=4.0.0,fixed=5.0.8.
- Is there a fix for CVE-2026-14257?
- Yes. brace-expansion (npm): upgrade to 5.0.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-14257 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-14257?
- Check whether you run brace-expansion (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- brace-expansion (npm): upgrade to 5.0.8 or later
npm install brace-expansion@5.0.8
Technical details
The `expand()` function in `brace-expansion` versions up to 5.0.7 fails to limit the total length of expanded strings, even though it limits the number of results. By chaining many brace groups (e.g., `'{a,b}'.repeat(1500)`), an attacker can force the library to create a massive number of intermediate 'cons-strings' (ropes) in the V8 engine. This leads to a fatal, uncatchable out-of-memory (OOM) error that terminates the Node.js process. The vulnerability can be triggered remotely if the application passes untrusted input to `expand()` or transitively via libraries like `minimatch` or `glob`. A fix is available in version 5.0.8 which introduces a `maxLength` option to bound total expansion size.
Affected products
- juliangruber brace-expansion <= 5.0.7
Identifiers
- CVE-2026-14257
- GHSA-mh99-v99m-4gvg
Timeline
- 2026-07-23: disclosed
- 2026-07-23: advisory: NVD publication date
- 2026-07-24: patched: GitHub Advisory reviewed and updated