CVE-2026-3276

Published: Jun 3, 2026Modified: Jul 22, 2026

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/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

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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/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:XShow less

Source: CNA (Secondary)

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.

Related CWEs

Inefficient Algorithmic Complexity

An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

References (9)

https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0

Source: cna@python.org

https://github.com/python/cpython/commit/90748760d38ca3ac5fc6788a69becab905c95598

Source: cna@python.org

https://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26f

Source: cna@python.org

https://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32

Source: cna@python.org

https://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066

Source: cna@python.org

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

Source: cna@python.org

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

Source: cna@python.org

https://mail.python.org/archives/list/security-announce@python.org/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/

Source: cna@python.org

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

Source: af854a3a-2127-422b-91ae-364da2661108

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