CVE-2026-119051 flat through 6.0.1 Denial of Service via unflatten() Numeric Array Index Keys
High 8.2
Published
Updated
Check this codebase for CVE-2026-119051 and fix it if it is affected.
What it is: CVE-2026-119051 is a high-severity vulnerability in hughsk flat, published on 29 Oct 2026.
Exploitation: There is no known exploitation of CVE-2026-119051 in the wild and no public exploit code.
Affected product: hughsk flat. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-119051/ (Markdown: https://insights.sbomify.com/CVE-2026-119051/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-119051?
CVE-2026-119051 is a high-severity vulnerability in hughsk flat, published on 29 Oct 2026.
Official description
flat through 6.0.1 contains an uncontrolled resource allocation vulnerability in unflatten() that allows attackers to create huge sparse arrays via unbounded numeric keys. Attackers can supply flattened keys such as a.4294967294, causing iteration with forEach, spread or JSON.stringify to block the Node.js event loop.
Weakness: CWE-770
Which versions are affected by CVE-2026-119051?
How do I fix CVE-2026-119051?
No fix has been published for CVE-2026-119051 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-119051 being exploited?
There is no known exploitation of CVE-2026-119051 in the wild and no public exploit code.
Sources
Also known as GHSA-476f-8ccp-82xp.