CVE-2026-3276

EUVD-2026-34103 · Published Jun 3, 2026

unicodedata.normalize() can take excessive CPU time when processing specially crafted Unicode input containing long runs of combining characters with alternating Canonical Combining Class values. This affects all normalization forms.

Weaknesses

CWE-407

CVSS scores

v4.06.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Initial Access

T1190Exploit Public-Facing Application

References

https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0
https://github.com/python/cpython/commit/90748760d38ca3ac5fc6788a69becab905c95598
https://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26f
https://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32
https://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066
https://github.com/python/cpython/issues/149079

Potentially impacted assets

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