CVE-2026-7210 PUBLISHED

The expat and elementtree parsers use insufficient entropy for XML hash-flooding protection

Assigner: PSF
Reserved: 27.04.2026 Published: 11.05.2026 Updated: 11.05.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS Score: 6.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	High	Integrity	None	Integrity	None
Attack Requirements	None	Availability	Low	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Python Software Foundation
Product	CPython
Versions	Default: unaffected affected from 0 to 3.15.0 (excl.)

Credits

Stan Ulbrych (https://github.com/StanFromIreland) coordinator
Gregory P. Smith (https://github.com/gpshead) remediation reviewer

References

Problem Types

CWE-331 Insufficient entropy CWE