CVE-2026-3276
CVE-2026-3276 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-407.
Key facts
- Severity: Medium (CVSS 4.0 base score 6.3)
- EPSS exploit prediction: 0% (39th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-34103
- Weakness: CWE-407
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-3276?
- 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.
- How severe is CVE-2026-3276?
- CVE-2026-3276 has a CVSS 4.0 base score of 6.3, rated medium severity.
- Is CVE-2026-3276 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-3276?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-3276 have an EU (EUVD) identifier?
- Yes. CVE-2026-3276 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34103.
- When was CVE-2026-3276 published?
- CVE-2026-3276 was published on 2026-06-03 and last updated on 2026-06-17.
References
- https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0
- https://github.com/python/cpython/commit/90748760d38ca3ac5fc6788a69becab905c95598
- https://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26f
- https://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32
- https://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066
- https://github.com/python/cpython/issues/149079
- https://github.com/python/cpython/pull/149080
- https://mail.python.org/archives/list/[email protected]/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/
- http://www.openwall.com/lists/oss-security/2026/06/03/15
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