# CVE-2026-127056: PapaParse before 5.7.1 Quadratic-Time Parsing DoS via indexOf Scan

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://www.npmjs.com/package/papaparse

## Affected products and versions

- mholt / PapaParse (papaparse): ≥ 0; < 5.7.1 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.7 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-407

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://www.npmjs.com/package/papaparse (CNA: VulnCheck; patch)

- https://github.com/mholt/PapaParse/commit/a50fe19aae08b966de444119333fe4a8b7aa6b2f (CNA: VulnCheck; issue-tracking)

- https://www.vulncheck.com/advisories/papaparse-before-quadratic-time-parsing-dos-via-indexof-scan (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-127056; retrieved 2026-11-12; source updated 2026-11-12

Revision: b6a2a29a7719f4e9f0c6704ade56ece63d65d995e2f9bbadab613ef4c074fe6b

Canonical: https://y2.dev/cve/CVE-2026-127056

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