CVE-2026-14257
HIGHbrace-expansion DoS via unbounded expansion length causing an out-of-memory process crash
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
brace-expansionnpmDescription
brace-expansion through 5.0.7 is vulnerable to denial of service via memory exhaustion. The expand() function limits the number of results with a max option (default 100,000) but does not bound the length of each result string. By chaining multiple brace groups, an attacker keeps the result count under the limit while making each result progressively longer, so total memory scales with both count and string length until the process hits a fatal, uncatchable out-of-memory error. About 7.5 KB of input ('{a,b}'.repeat(1500)) crashes a default Node.js process. 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. Fixed in 5.0.8 by adding a maxLength option (default 4,000,000) that bounds accumulated output and intermediate arrays.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | brace-expansion | all versions | 5.0.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for brace-expansion. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update brace-expansion to 5.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-14257 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-14257 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-14257. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-14257 in your dependencies?
O3 detects CVE-2026-14257 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.