CVE-2026-7210: CWE-331 Insufficient entropy in Python Software Foundation CPython
`xml.parsers.expat` and `xml.etree.ElementTree` use insufficient entropy for Expat hash-flooding protection, which allows a crafted XML document to trigger hash flooding.\r\n\r\nFully mitigating this vulnerability requires both updating libexpat to 2.8.0 or later and applying this patch.
AI Analysis
Technical Summary
The vulnerability CVE-2026-7210 in CPython arises from insufficient entropy in the hash-flooding protection mechanism of the xml.parsers.expat and xml.etree.ElementTree modules. This weakness allows an attacker to craft XML documents that can trigger hash flooding attacks. Effective mitigation requires both updating the underlying libexpat library to version 2.8.0 or later and applying a corresponding patch to CPython. No official remediation level or patch links are provided in the available data.
Potential Impact
An attacker can exploit this vulnerability by crafting XML documents that cause hash flooding, potentially leading to denial of service or degraded performance in applications parsing XML with the affected CPython modules. The CVSS 4.0 score is 6.3 (medium severity), indicating a network attack vector with high complexity and limited impact (low availability impact). There are no known exploits in the wild at this time.
Mitigation Recommendations
No official patch or remediation level is currently confirmed. Full mitigation requires updating libexpat to version 2.8.0 or later and applying a patch to CPython. Patch status is not yet confirmed — check the Python Software Foundation advisory for current remediation guidance.
CVE-2026-7210: CWE-331 Insufficient entropy in Python Software Foundation CPython
Description
`xml.parsers.expat` and `xml.etree.ElementTree` use insufficient entropy for Expat hash-flooding protection, which allows a crafted XML document to trigger hash flooding.\r\n\r\nFully mitigating this vulnerability requires both updating libexpat to 2.8.0 or later and applying this patch.
CVSS v4.0
Score 6.3medium
Affected software
Python Software Foundation
CPython
pkg:github/CPythonRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-7210 in CPython arises from insufficient entropy in the hash-flooding protection mechanism of the xml.parsers.expat and xml.etree.ElementTree modules. This weakness allows an attacker to craft XML documents that can trigger hash flooding attacks. Effective mitigation requires both updating the underlying libexpat library to version 2.8.0 or later and applying a corresponding patch to CPython. No official remediation level or patch links are provided in the available data.
Potential Impact
An attacker can exploit this vulnerability by crafting XML documents that cause hash flooding, potentially leading to denial of service or degraded performance in applications parsing XML with the affected CPython modules. The CVSS 4.0 score is 6.3 (medium severity), indicating a network attack vector with high complexity and limited impact (low availability impact). There are no known exploits in the wild at this time.
Mitigation Recommendations
No official patch or remediation level is currently confirmed. Full mitigation requires updating libexpat to version 2.8.0 or later and applying a patch to CPython. Patch status is not yet confirmed — check the Python Software Foundation advisory for current remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- PSF
- Date Reserved
- 2026-04-27T14:43:40.042Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a021aa7cbff5d861043053d
Added to database: 05/11/2026, 18:06:31 UTC
Last enriched: 08/12/2026, 13:13:54 UTC
Last updated: 09/10/2026, 22:05:07 UTC
Views: 399
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