CVE-2026-3276

medium

Description

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.

References

https://mail.python.org/archives/list/[email protected]/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/

https://github.com/python/cpython/pull/149080

https://github.com/python/cpython/issues/149079

http://www.openwall.com/lists/oss-security/2026/06/03/15

Details

Source: Mitre, NVD

Published: 2026-06-03

Updated: 2026-06-03

Risk Information

CVSS v2

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P

Severity: Medium

CVSS v3

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

CVSS v4

Base Score: 6.3

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