CVE-2026-33750 is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in brace-expansion. A fix is available for brace-expansion — see the affected versions and patch details below.
brace-expansion: Zero-step sequence causes process hang and memory exhaustion
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33750.
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.
How urgent is this, really
CVE-2026-33750 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
brace-expansionnpmDescription
The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13, a brace pattern with a zero step value (e.g., {1..2..0}) causes the sequence generation loop to run indefinitely, making the process hang for seconds and allocate heaps of memory. Versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13 fix the issue. As a workaround, sanitize strings passed to expand() to ensure a step value of 0 is not used.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | brace-expansion | ≥ 4.0.0&&< 5.0.5 | 5.0.5npm install brace-expansion@5.0.5 |
| 📦npm | brace-expansion | ≥ 3.0.0&&< 3.0.2 | 3.0.2npm install brace-expansion@3.0.2 |
| 📦npm | brace-expansion | ≥ 2.0.0&&< 2.0.3 | 2.0.3npm install brace-expansion@2.0.3 |
| 📦npm | brace-expansion | all versions | 1.1.13npm install brace-expansion@1.1.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for brace-expansion, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update brace-expansion to 5.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33750 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33750 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33750. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability has been rated as Moderate by Red Hat. The vulnerability requires parsing a malformed pattern that, when parsed, leads to infinite looping, excessive memory allocation, and could result in a DoS. The flaw is rated as Moderate because the vulnerable code in the brace-expansion library is not exposed…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Openshift Data Foundation 4.18 | odf4/cephcsi-rhel9:1786705347 | RHSA-2026:56431 |
| Red Hat Openshift Data Foundation 4.22 | odf4/cephcsi-rhel9:1787057250 | RHSA-2026:56928 |
Frequently Asked Questions
Is CVE-2026-33750 in your dependencies?
O3 Security finds CVE-2026-33750 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.