---
id: "CVE-2026-127056"
page: "https://infrastack.ai/live/CVE-2026-127056"
kind: "vulnerability"
aliases: ["CVE-2026-127056"]
title: "PapaParse: crafted quoted CSV input causes quadratic CPU denial of service"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "papaparse", "fixed": [], "affected": "", "ecosystem": "npm"}]
ecosystems: ["npm"]
tags: ["browser", "node.js", "package", "papaparse"]
not_affected_if: ["papaparse-5.7.1-or-later", "trusted-input-only"]
published_at: "2026-11-12T13:17:16+00:00"
first_seen_at: "2026-11-12T13:38:24+00:00"
updated_at: "2026-11-12T13:38:42+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-127056", "first_seen_at": "2026-11-12T13:38:24+00:00"}]
exploit_sources: []
---

# PapaParse: crafted quoted CSV input causes quadratic CPU denial of service

Link for people: https://infrastack.ai/live/CVE-2026-127056 (this .md is for agents)

PapaParse before 5.7.1 parses delimiter-free quoted CSV input with repeated full-buffer scans that grow quadratically with input size. An unauthenticated attacker can exhaust CPU, blocking the Node.js event loop or freezing a browser tab.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- npm:papaparse affected range not listed fixed no fixed version listed

## How to check

- Look for the `papaparse` package in `package.json` and lockfiles, and check the installed version with `npm ls papaparse`.
- Find code calling `Papa.parse()` on input an outside party can supply, such as uploads or API request bodies.

## Fix

- `papaparse` 5.7.1 or later (the fix is in the 5.7.1 release; the sources do not list other branches).

## Timeline

- 2026-11-12T13:38:24+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-127056

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/papaparse-before-quadratic-time-parsing-dos-via-indexof-scan
- [fix] Patch: github.com https://github.com/mholt/PapaParse/commit/a50fe19aae08b966de444119333fe4a8b7aa6b2f

## From the sources

PapaParse before 5.7.1 contains an inefficient algorithmic complexity vulnerability that allows remote unauthenticated attackers to cause denial of service by submitting delimiter-free quoted CSV input to Papa.parse(). Attackers can supply a single-column quoted CSV with no delimiters, triggering repeated full-buffer indexOf scans per row that grow quadratically with input size, exhausting CPU and blocking the Node.js event loop or freezing a browser tab.

---

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