CVE-2026-25673
Potential denial-of-service vulnerability in URLField via Unicode normalization on Windows
- Published
- Updated
- Reserved
- Assigned by
- DSF
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| redhat-SADPADP (enrichment) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.84% · top 42% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
- affected 6.0 – < 6.0.3
- unaffected 6.0.3
- affected 5.2 – < 5.2.12
- unaffected 5.2.12
- affected 4.2 – < 4.2.29
- unaffected 4.2.29
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIDjangoGHSA-8p8v-wh79-9r56 (opens in a new tab)
References (6)
- Django security archive (opens in a new tab)vendor-advisory
- Django releases announcements (opens in a new tab)mailing-list
- Django security releases issued: 6.0.3, 5.2.12, and 4.2.29 (opens in a new tab)vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-25673 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2444115 (opens in a new tab)issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25673.json (opens in a new tab)x_sadp-csaf-vex
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-8p8v-wh79-9r56 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-25673)Record last updated .