CVE-2026-3276
Potential DoS via quadratic complexity in unicodedata.normalize()
- State
- Published
- Severity
- 6.3 Medium
- Published
- Jun 3, 2026
- Updated
- Aug 13, 2026
- Reserved
- Feb 26, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | 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 | PSF |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://mail.python.org/archives/list/security-announce@python.org/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/vendor-advisory
- https://github.com/python/cpython/pull/149080patch
- https://github.com/python/cpython/issues/149079issue-tracking
- https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0patch
- https://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26fpatch
- https://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32patch
- https://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066patch
- https://github.com/python/cpython/commit/90748760d38ca3ac5fc6788a69becab905c95598patch
- https://github.com/python/cpython/commit/d3ab945af25b28dfe13ac6cb40c124a01b33ce1fpatch
- https://github.com/python/cpython/commit/db744c0776c1d5dd11aaa70eff2a6993c408baccpatch
- https://github.com/python/cpython/commit/e322a1857084d521f79f45181b776f62e6acfc2cpatch
- http://www.openwall.com/lists/oss-security/2026/06/03/15
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