CVE-2025-54363
Withdrawn Advisory: Microsoft Knack ReDoS Vulnerability in the Introspection Module
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
6.9
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
- Record
CVE-2025-54363- CVSS 4.0
- 6.9 Medium
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 - Weakness
- CWE-1333
- Updated
- 2026-11-02
EUVDEUVD-2025-25266
6.9
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
- Record
EUVD-2025-25266- CVSS 4.0
- 6.9 Medium
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6fxp-p9mg-q64w
1.2
Withdrawn Advisory: Microsoft Knack ReDoS Vulnerability in the Introspection Module
Withdrawn Advisory
This advisory has been withdrawn because the attack surface of this vulnerability is outside of Knack's intended functionality. The maintainer states the following:
These CVEs are invalid. Knack is a CLI framework used by Azure CLI. It's a local library, not a web service. In addition, the regex is used to extract function and parameter docstrings from the source code. It is not used to match user input. Therefore, it does not expose any attack surface. There is no way to use it for ReDoS attack.
This link is maintained to preserve external references.
Original Description
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module (issue 1 of 2).
- Record
GHSA-6fxp-p9mg-q64w- CVSS 4.0
- 1.2 Low
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U - Weakness
- CWE-1333
- Updated
- 2026-11-02
NVD
6.9
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
- Record
CVE-2025-54363- CVSS 4.0
- 6.9 Medium
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSV
6.9
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
- Record
CVE-2025-54363- CVSS 4.0
- 6.9 Medium
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 - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2025-54363
6.9
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
- Record
DEBIAN-CVE-2025-54363- CVSS 4.0
- 6.9 Medium
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-02
OSVGHSA-6fxp-p9mg-q64w
1.2
Withdrawn Advisory: Microsoft Knack ReDoS Vulnerability in the Introspection Module
Withdrawn Advisory
This advisory has been withdrawn because the attack surface of this vulnerability is outside of Knack's intended functionality. The maintainer states the following:
These CVEs are invalid. Knack is a CLI framework used by Azure CLI. It's a local library, not a web service. In addition, the regex is used to extract function and parameter docstrings from the source code. It is not used to match user input. Therefore, it does not expose any attack surface. There is no way to use it for ReDoS attack.
This link is maintained to preserve external references.
Original Description
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module (issue 1 of 2).
- Record
GHSA-6fxp-p9mg-q64w- CVSS 4.0
- 1.2 Low
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-54363
6.9
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature 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.
- Record
UBUNTU-CVE-2025-54363- CVSS 4.0
- 6.9 Medium
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 - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
knackDebian:12 |
All versions, plus listed versions 0.10.1-10.11.0-10.11.0-1~bpo12+10.12.0-10.12.0-1~bpo12+10.12.0-20.13.0-10.14.0-1 |
None known |
knackDebian:13 |
All versions, plus listed versions 0.12.0-20.13.0-10.14.0-1 |
None known |
knackDebian:14 |
All versions, plus listed versions 0.12.0-20.13.0-10.14.0-1 |
None known |
knackUbuntu:20.04:LTS |
All versions, plus listed versions 0.6.2-1ubuntu10.6.3-1ubuntu10.6.3-2~build10.6.3-2 |
None known |
knackUbuntu:22.04:LTS |
All versions, plus listed versions 0.8.0~rc2-10.9.0-1 |
None known |
knackUbuntu:24.04:LTS |
All versions, plus listed versions 0.11.0-1 |
None known |
knackUbuntu:25.10 |
All versions, plus listed versions 0.12.0-2 |
None known |
knackUbuntu:26.10 |
All versions, plus listed versions 0.13.0-10.14.0-1 |
None known |
knackUbuntu:26.04:LTS |
All versions, plus listed versions 0.12.0-20.13.0-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-54363 is a medium vulnerability (CVSS 6.9) in Microsoft Knack, published August 20, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 36th percentile. No source names a fixed version.
References
github.com/microsoft/knack
vulncheck.com/advisories/microsoft-knack-python-package-regular-expression-dos
github.com/microsoft/knack/issues/281
nvd.nist.gov/vuln/detail/CVE-2025-54363
github.com/advisories/GHSA-6fxp-p9mg-q64w
github.com/CVEProject/cvelistV5/tree/main/cves/2025/54xxx/CVE-2025-54363.json
security-tracker.debian.org/tracker/CVE-2025-54363
ubuntu.com/security/CVE-2025-54363
cve.org/CVERecord?id=CVE-2025-54363