CVE-2026-25673 | Potential denial-of-service vulnerability in URLField via Unicode normalization on Windows

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.

Published: 2026-03-03 Last update: 2026-03-05 Assigner: 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92 Source: 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-25673 is rated Moderate Risk (42.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.16%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-25673

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-09 0.10% 0.16% +0.06%
2 2026-03-04 — 0.10% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-25673

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-25673

GitHub Security Advisory for CVE-2026-25673

GHSA-8p8v-wh79-9r56 · Severity: high · Ecosystem: pip — Django vulnerable to Uncontrolled Resource Consumption

OS Trackers for CVE-2026-25673

vendor priority summary link
alpine — CVE-2026-25673: 1 source package rows (py3-django); 1 state rows across 1 repos (3.23-community); fixed 1, open 0. https://security.alpinelinux.org/vuln/CVE-2026-25673
debian unimportant CVE-2026-25673 unimportant priority: Debian including 1 source packages (python-django), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-25673
redhat high — https://access.redhat.com/security/cve/CVE-2026-25673
suse high CVE-2026-25673 severity important: SUSE including 2 source package names (python-Django, python311-Django), 4 product×package rows across 2 product lines (SUSE Linux Enterprise Module for Package Hub 15 SP7, openSUSE Leap 15.6): Known Not Affected 4. https://www.suse.com/security/cve/CVE-2026-25673/
ubuntu medium CVE-2026-25673 medium priority: Ubuntu including 1 source packages (python-django), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): not-affected 7, needs-triage 1. https://ubuntu.com/security/CVE-2026-25673

Affected software / configurations for CVE-2026-25673

Vendor Product Version Raw CPE
djangoproject django >= 4.2.0, < 4.2.29 cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*
djangoproject django >= 5.2, < 5.2.12 cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*
djangoproject django >= 6.0, < 6.0.3 cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*

References for CVE-2026-25673

cvelogic Threat Intelligence