CVE-2026-3276
Vulnerability Summary
Timeline
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.
CVSS Metrics
- v4.0•MEDIUM•Score: 6.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- v4.0•MEDIUM•Score: 6.3CVSS: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
EPSS Trends
Current EPSS score: 0.49%• Percentile: 41%
Techniques & Countermeasures
- CWE-407•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.
Affected Systems
- alpine•python3
< 3.14.7-r0
- chainguard•python-3.10
< 3.10.20-r8
- chainguard•python-3.11
< 3.11.15-r6
- chainguard•python-3.12
< 3.12.13-r8
- chainguard•python-3.13
< 3.13.14-r0
- chainguard•python-3.14
< 3.14.6-r0
- wolfi•python-3.10
< 3.10.20-r8
- wolfi•python-3.11
< 3.11.15-r6
- wolfi•python-3.12
< 3.12.13-r8
- wolfi•python-3.13
< 3.13.14-r0
- wolfi•python-3.14
< 3.14.6-r0
- debian•python2.7
all
- debian•python3.11
all
- debian•python3.13
< 3.13.5-2+deb13u3 | < 3.13.14-1
- debian•python3.14
< 3.14.6-1
- debian•python3.9
all
- ubuntu•pypy3
all | all | all | all | all
- ubuntu•python2.7
all
- ubuntu•python3.10
< 3.10.12-1~22.04.16
- ubuntu•python3.11
all | all
- ubuntu•python3.12
< 3.12.3-1ubuntu0.15
- ubuntu•python3.13
all
- ubuntu•python3.14
all | < 3.14.4-1ubuntu0.1
- ubuntu•python3.4
all
- ubuntu•python3.5
all
- ubuntu•python3.6
all
- ubuntu•python3.7
all
- ubuntu•python3.8
all
- ubuntu•python3.9
all
- python software foundation•cpython
All versions | < 3.15.0 | < 3.15.0b2 | < 3.13.14 | < 3.10.21 | ≥ 3.11.0, < 3.11.16 | ≥ 3.12.0, < 3.12.14 | ≥ 3.13.0, < 3.13.14 | ≥ 3.14.0, < 3.14.6 | ≥ 3.15.0a1, < 3.15.0b2
- suse•python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise Module for Public Cloud 15 SP4
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise Server 15 SP4-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise Server 15 SP5-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise Server for SAP Applications 15 SP4
< 3.11.15-150400.9.97.1
- suse•python311-core&distro=SUSE Linux Enterprise Server for SAP Applications 15 SP5
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise Server 15 SP4-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise Server 15 SP5-LTSS
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise Server for SAP Applications 15 SP4
< 3.11.15-150400.9.97.1
- suse•python311-documentation&distro=SUSE Linux Enterprise Server for SAP Applications 15 SP5
< 3.11.15-150400.9.97.1
- suse•python311&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS
< 3.11.15-150400.9.97.1
- suse•python311&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
< 3.11.15-150400.9.97.1
- suse•python311&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS
< 3.11.15-150400.9.97.1
Showing first 50 affected entries in server-rendered view.
References (24)
- https://mail.python.org/archives/list/security-announce@python.org/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
- https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0
- 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/commit/90748760d38ca3ac5fc6788a69becab905c95598
- https://github.com/python/cpython/commit/d3ab945af25b28dfe13ac6cb40c124a01b33ce1f
- https://github.com/python/cpython/commit/db744c0776c1d5dd11aaa70eff2a6993c408bacc
- https://github.com/python/cpython/commit/e322a1857084d521f79f45181b776f62e6acfc2c
- https://ubuntu.com/security/CVE-2026-3276
- https://www.cve.org/CVERecord?id=CVE-2026-3276
- https://www.openwall.com/lists/oss-security/2026/06/03/15
- https://ubuntu.com/security/notices/USN-8509-1
- https://security-tracker.debian.org/tracker/CVE-2026-3276
- https://security.alpinelinux.org/vuln/CVE-2026-3276
- https://www.suse.com/support/update/announcement/2026/suse-su-20263655-1/
- https://bugzilla.suse.com/1263083
- https://www.suse.com/security/cve/CVE-2026-3276
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3276.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-3276
- https://github.com/python/cpython