`URLField.to_python()` in Django calls `urllib.parse.urlsplit()`, which performs NFKC normalization on Windows that is disproportionately slow for certain Unicode characters, allowing a remote attacker to cause denial of service via large URL inputs containing these characters.
Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected.
Django would like to thank Seokchan Yoon for reporting this issue.
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Workaround
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Tue, 03 Mar 2026 16:15:00 +0000
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Tue, 03 Mar 2026 14:45:00 +0000
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| Description | An issue was discovered in 6.0 before 6.0.3, 5.2 before 5.2.12, and 4.2 before 4.2.29. `URLField.to_python()` in Django calls `urllib.parse.urlsplit()`, which performs NFKC normalization on Windows that is disproportionately slow for certain Unicode characters, allowing a remote attacker to cause denial of service via large URL inputs containing these characters. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Seokchan Yoon for reporting this issue. | |
| Title | Potential denial-of-service vulnerability in URLField via Unicode normalization on Windows | |
| Weaknesses | CWE-400 | |
| References |
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Status: PUBLISHED
Assigner: DSF
Published:
Updated: 2026-03-03T15:26:02.764Z
Reserved: 2026-02-04T18:27:10.657Z
Link: CVE-2026-25673
Updated: 2026-03-03T15:25:39.933Z
Status : Received
Published: 2026-03-03T15:16:19.103
Modified: 2026-03-03T16:16:20.970
Link: CVE-2026-25673
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OpenCVE Enrichment
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