CVE-2026-3276

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 61% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
6.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.3Exploit: NoneExposed: 0

A fix is available — apply it.

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 v3
6.3
EG Score
6.3(medium)
EPSS
39.3%
KEV
Not listed

Published

June 3, 2026

Last Modified

July 22, 2026

Advisory Details (8)

Auto-updated Jun 13, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
generic

oss-security - [CVE-2026-3276] Potential DoS via quadratic complexity in unicodedata.normalize()

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

Mailman 3 [CVE-2026-3276] Potential DoS via quadratic complexity in unicodedata.normalize() - Security-announce - python.org

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

gh-149079: Fix O(n^2) canonical ordering in unicodedata.normalize()

Fix merged in python/cpython PR #149080 on 2026-06-02 — awaiting tagged release

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

Issue · GitHub

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

commit c5512bd7c1dc (python/cpython)

Fix landed in python/cpython commit c5512bd7c1dc — awaiting tagged release

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

commit ba785b88add9 (python/cpython)

Fix landed in python/cpython commit ba785b88add9 — awaiting tagged release

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

commit 991224b1e831 (python/cpython)

Fix landed in python/cpython commit 991224b1e831 — awaiting tagged release

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

commit 6b505d1f41f8 (python/cpython)

Fix landed in python/cpython commit 6b505d1f41f8 — awaiting tagged release

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

Vendor Advisories for CVE-2026-3276(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupython3.12-venv (3.12.3-1ubuntu0.15) @ noble2026-07-16ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 9× in last 7d / 53× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 02:29 UTCEPSS rescore
  6. 2026-07-18 10:04 UTCEPSS rescore
  7. 2026-07-16 17:03 UTCEPSS rescore
  8. 2026-07-16 00:38 UTCVendor advisory
  9. 2026-07-16 00:38 UTCGHSA enrichment
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-14 03:30 UTCVendor advisory
  14. 2026-07-14 03:30 UTCGHSA enrichment
  15. 2026-07-13 22:30 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-12 05:46 UTCEPSS rescore
  19. 2026-07-11 12:43 UTCVendor advisory
  20. 2026-07-11 12:43 UTCGHSA enrichment
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-09 19:10 UTCEPSS rescore
  23. 2026-07-08 16:26 UTCVendor advisory
  24. 2026-07-08 16:26 UTCGHSA enrichment
  25. 2026-07-08 15:15 UTCEPSS rescore
Show 74 more
  1. 2026-07-07 13:46 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 02:30 UTCEPSS rescore
  7. 2026-07-04 06:31 UTCEPSS rescore
  8. 2026-07-03 23:37 UTCGHSA enrichment
  9. 2026-07-02 23:25 UTCGHSA enrichment
  10. 2026-07-01 23:22 UTCGHSA enrichment
  11. 2026-07-01 15:06 UTCEPSS rescore
  12. 2026-06-30 23:22 UTCEPSS rescore
  13. 2026-06-30 23:14 UTCGHSA enrichment
  14. 2026-06-29 23:11 UTCGHSA enrichment
  15. 2026-06-29 14:06 UTCEPSS rescore
  16. 2026-06-28 23:00 UTCGHSA enrichment
  17. 2026-06-28 14:07 UTCEPSS rescore
  18. 2026-06-28 04:56 UTCEPSS rescore
  19. 2026-06-27 22:58 UTCGHSA enrichment
  20. 2026-06-27 03:08 UTCEPSS rescore
  21. 2026-06-26 22:56 UTCGHSA enrichment
  22. 2026-06-25 22:35 UTCGHSA enrichment
  23. 2026-06-25 13:49 UTCEPSS rescore
  24. 2026-06-25 13:49 UTCEPSS rescore
  25. 2026-06-24 22:22 UTCGHSA enrichment
  26. 2026-06-24 14:05 UTCEPSS rescore
  27. 2026-06-23 21:33 UTCEPSS rescore
  28. 2026-06-23 19:07 UTCGHSA enrichment
  29. 2026-06-22 14:25 UTCEPSS rescore
  30. 2026-06-22 14:25 UTCEPSS rescore
  31. 2026-06-21 14:56 UTCEPSS rescore
  32. 2026-06-21 14:56 UTCEPSS rescore
  33. 2026-06-21 01:59 UTCEPSS rescore
  34. 2026-06-19 23:52 UTCGHSA enrichment
  35. 2026-06-19 19:25 UTCEPSS rescore
  36. 2026-06-18 21:33 UTCGHSA enrichment
  37. 2026-06-18 17:52 UTCEPSS rescore
  38. 2026-06-18 17:52 UTCEPSS rescore
  39. 2026-06-17 19:10 UTCGHSA enrichment
  40. 2026-06-17 17:53 UTCEPSS rescore
  41. 2026-06-16 19:08 UTCGHSA enrichment
  42. 2026-06-16 17:52 UTCEPSS rescore
  43. 2026-06-15 19:03 UTCGHSA enrichment
  44. 2026-06-15 17:49 UTCEPSS rescore
  45. 2026-06-14 23:18 UTCEPSS rescore
  46. 2026-06-14 18:45 UTCGHSA enrichment
  47. 2026-06-13 23:00 UTCEPSS rescore
  48. 2026-06-13 18:44 UTCGHSA enrichment
  49. 2026-06-12 23:12 UTCEPSS rescore
  50. 2026-06-12 23:12 UTCEPSS rescore
  51. 2026-06-12 18:12 UTCGHSA enrichment
  52. 2026-06-11 18:10 UTCGHSA enrichment
  53. 2026-06-11 14:00 UTCEPSS rescore
  54. 2026-06-10 22:18 UTCEPSS rescore
  55. 2026-06-10 18:09 UTCGHSA enrichment
  56. 2026-06-10 13:22 UTCEPSS rescore
  57. 2026-06-09 18:07 UTCGHSA enrichment
  58. 2026-06-08 18:06 UTCGHSA enrichment
  59. 2026-06-08 14:17 UTCEPSS rescore
  60. 2026-06-08 14:17 UTCEPSS rescore
  61. 2026-06-07 15:54 UTCGHSA enrichment
  62. 2026-06-07 15:25 UTCEPSS rescore
  63. 2026-06-07 15:25 UTCEPSS rescore
  64. 2026-06-07 15:25 UTCEPSS rescore
  65. 2026-06-06 15:53 UTCGHSA enrichment
  66. 2026-06-06 13:47 UTCEPSS rescore
  67. 2026-06-06 13:47 UTCEPSS rescore
  68. 2026-06-05 22:47 UTCEPSS rescore
  69. 2026-06-05 22:47 UTCEPSS rescore
  70. 2026-06-05 15:52 UTCGHSA enrichment
  71. 2026-06-05 06:10 UTCEPSS rescore
  72. 2026-06-05 06:10 UTCEPSS rescore
  73. 2026-06-04 15:51 UTCGHSA enrichment
  74. 2026-06-03 15:50 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-3276?
CVE-2026-3276 is a medium vulnerability published on June 3, 2026. 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.
When was CVE-2026-3276 disclosed?
CVE-2026-3276 was first published in the National Vulnerability Database on June 3, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-3276 actively exploited?
CVE-2026-3276 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 39.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-3276?
CVE-2026-3276 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-3276?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-3276, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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