CVE-2025-6069: CWE-1333 Inefficient Regular Expression Complexity in Python Software Foundation CPython
The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.
AI Analysis
Technical Summary
The html.parser.HTMLParser class in CPython versions 0, 3.11.0, 3.12.0, 3.13.0, and 3.14.0a1 suffers from inefficient regular expression complexity (CWE-1333). Specifically, processing certain crafted malformed inputs causes worst-case quadratic time complexity, which can be exploited to cause amplified denial-of-service by exhausting CPU resources. This vulnerability does not impact confidentiality or integrity but affects availability. The CVSS 3.1 base score is 4.3 (medium severity) with network attack vector, low attack complexity, requiring low privileges and no user interaction.
Potential Impact
The vulnerability can lead to denial-of-service conditions by causing the html.parser.HTMLParser to consume excessive CPU resources when processing specially crafted malformed inputs. There is no impact on confidentiality or integrity. No known exploits are reported in the wild at this time.
Mitigation Recommendations
No official patch or fix is currently documented for this vulnerability. Users should monitor the Python Software Foundation's advisories for updates and apply any forthcoming patches promptly. Until a fix is available, consider limiting exposure of vulnerable components to untrusted input or employing input validation to mitigate potential denial-of-service attempts.
CVE-2025-6069: CWE-1333 Inefficient Regular Expression Complexity in Python Software Foundation CPython
Description
The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The html.parser.HTMLParser class in CPython versions 0, 3.11.0, 3.12.0, 3.13.0, and 3.14.0a1 suffers from inefficient regular expression complexity (CWE-1333). Specifically, processing certain crafted malformed inputs causes worst-case quadratic time complexity, which can be exploited to cause amplified denial-of-service by exhausting CPU resources. This vulnerability does not impact confidentiality or integrity but affects availability. The CVSS 3.1 base score is 4.3 (medium severity) with network attack vector, low attack complexity, requiring low privileges and no user interaction.
Potential Impact
The vulnerability can lead to denial-of-service conditions by causing the html.parser.HTMLParser to consume excessive CPU resources when processing specially crafted malformed inputs. There is no impact on confidentiality or integrity. No known exploits are reported in the wild at this time.
Mitigation Recommendations
No official patch or fix is currently documented for this vulnerability. Users should monitor the Python Software Foundation's advisories for updates and apply any forthcoming patches promptly. Until a fix is available, consider limiting exposure of vulnerable components to untrusted input or employing input validation to mitigate potential denial-of-service attempts.
Technical Details
- Data Version
- 5.1
- Assigner Short Name
- PSF
- Date Reserved
- 2025-06-13T14:05:15.473Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 68517269a8c921274385c3c5
Added to database: 6/17/2025, 1:49:29 PM
Last enriched: 4/22/2026, 5:42:49 AM
Last updated: 5/8/2026, 7:11:13 PM
Views: 108
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