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Medium 6.3Published Jun 3, 2026
CVE-2026-3276Potential DoS via quadratic complexity in unicodedata.normalize()
Updated under an hour ago ()
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It affects Python Software Foundation CPython. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.3 MEDIUM (v4.0, CNA)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
- Weakness (CWE)
- CWE-407
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- PSF
- NVD analysis
- Awaiting Analysis
- Record last updated
- Aug 12, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Python Software Foundation CPython python_software_foundation:cpython (from the name) | before 3.10.21; from 3.11.0 before 3.11.16; from 3.12.0 before 3.12.14; from 3.13.0 before 3.13.14; from 3.14.0 before 3.14.6; from 3.15.0a1 before 3.15.0b2 | CNA record |
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
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.