---
id: CVE-2026-67199
title: >-
  Perspective 5.0.0 contains a denial of service vulnerability that allows
  remote attackers to block the server event loop indefinitely by submitting a
  crafted expression containing unbounded for or while loop constructs in a
  TableMakeView…
summary: >-
  Perspective 5.0.0 contains a denial of service vulnerability that allows
  remote attackers to block the server event loop indefinitely by submitting a
  crafted expression containing unbounded for or while loop constructs in a
  TableMakeView…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
published: '2026-08-04'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T20:35:08.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67199'
references:
  - url: 'https://christbowel.com/blog/perspective-5-0-0-five-cves/'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/perspective-dos-via-loop-expression-evaluation
    label: disclosure@vulncheck.com
  - url: 'https://christbowel.com/blog/perspective-5-0-0-five-cves/'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00519
epssPercentile: 0.41614
ingestedAt: '2026-09-09T21:22:45.522Z'
---

## Overview

Perspective 5.0.0 contains a denial of service vulnerability that allows remote attackers to block the server event loop indefinitely by submitting a crafted expression containing unbounded for or while loop constructs in a TableMakeViewReq message. Attackers can embed an arbitrarily large iteration count in an expression column evaluated once per table row, causing the Tornado IOLoop to block without any iteration cap, deadline, or cancellation check, rendering the server unresponsive to all connected clients.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.