CVE-2025-54364 Denial of service in Knack
An attacker can cause excessive CPU consumption and denial of service in applications using Microsoft Knack by injecting crafted docstrings that trigger catastrophic backtracking in regular expressions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-54364?
CVE-2025-54364 is a medium-severity denial of service vulnerability in Microsoft Knack, published on 20 Aug 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-1333
Which versions are affected by CVE-2025-54364?
How do I fix CVE-2025-54364?
No fix has been published for CVE-2025-54364 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-54364 being exploited?
There is no known exploitation of CVE-2025-54364 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2025-54364, UBUNTU-CVE-2025-54364.