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CVE-2026-119051high8.2

flat through 6.0.1 Denial of Service via unflatten() Numeric Array Index Keys

Impact

flat through 6.0.1 has a denial of service vulnerability via unflatten() due to uncontrolled resource allocation, allowing attackers to create huge sparse arrays. Attackers can supply specific flattened keys, blocking the Node.js event loop.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Affected packages

This source has no supported package-version data for matching. You can read the advisory here, but this record alone cannot power a dependency check.

Affected products

Vendor version evidence. Product records are separate from automatic dependency matching.

hughsk · VulnCheck

flat

1 range
VulnCheck version evidence

Package identity

pkg:npm/flatExplore flat →

Identity supplied by VulnCheck. Version matching requires compatible range evidence.

Compare with this publisher’s ranges. This does not inspect your installation.

affected

0 → through 6.0.1

custom versions

unaffected

unknown

Other versions: unaffected

Original source 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.

Inside the record

Evidence available

Package identity
Version evidence
Remediation guidance · not supplied
Weakness classification
Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-119051

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-770 ↗

Allocation of Resources Without Limits or Throttling

VulnCheck

Related →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

VulnCheck · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:a:flat_project:flat:*:*:*:*:*:*:*:*

Through (inclusive): 6.0.1

Original applicability statements
[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:a:flat_project:flat:*:*:*:*:*:*:*:*",
            "versionEndIncluding": "6.0.1"
          }
        ]
      }
    ]
  }
]
Contributing organizations · 1
VulnCheck

Assigning organization

2026-10-29

What changed

Follow changes
No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.

References

5 sources
github.com/hughsk/flat/issues/195
issue-trackingVulnCheck
github.com/hughsk/flat
productVulnCheck
github.com/hughsk/flat/blob/1d68e1d06c0210cff31e5c61ac177f3e2d3fa564/index.js
technical-descriptionVulnCheck
github.com/hughsk/flat/blob/1d68e1d06c0210cff31e5c61ac177f3e2d3fa564/index.js
technical-descriptionVulnCheck
www.vulncheck.com/advisories/flat-through-6.0.1-denial-of-service-via-unflatten-numeric-array-index-keys
third-party-advisoryVulnCheck