CVE-2026-119051
flat through 6.0.1 Denial of Service via unflatten() Numeric Array Index Keys
- State
- Published
- Severity
- 8.2 High
- Published
- Oct 29, 2026
- Updated
- Oct 29, 2026
- Reserved
- Oct 29, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.2 High | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
flathughsk |
|
References
- GitHub Issue #195issue-tracking
- https://github.com/hughsk/flatproduct
- https://github.com/hughsk/flat/blob/1d68e1d06c0210cff31e5c61ac177f3e2d3fa564/index.js#L65-L75technical-description
- https://github.com/hughsk/flat/blob/1d68e1d06c0210cff31e5c61ac177f3e2d3fa564/index.js#L137-L142technical-description
- VulnCheck Advisory: flat through 6.0.1 Denial of Service via unflatten() Numeric Array Index Keysthird-party-advisory
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