CVE-2026-3276 MEDIUM

CVE-2026-3276: Potential DoS via quadratic complexity in unicodedata.normalize()

Vendor Python Software Foundation
Product CPython
Weakness CWE-407
Published June 3, 2026
Last update June 10, 2026
View on NVD All CVEs

CVSS base score

6.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

June 3, 2026 CVE published
June 10, 2026 Record updated