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Fencer Vulns
high 7.5

CVE-2009-3695 json

Django Regex Algorithmic Complexity Causes Denial of Service

published 2009-10-13 17 y ago modified 2026-06-16 4 mo ago also GHSA-p6m5-h7pp-v2x5 , PYSEC-2009-4 , EUVD-2009-0004

cvss
7.5
version 3.1, GitHub
cisa kev
Not listed
not in CISA's catalog
epss
3.8%
EPSS 3.8% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

Algorithmic complexity vulnerability in the forms library in Django 1.0 before 1.0.4 and 1.1 before 1.1.1 allows remote attackers to cause a denial of service (CPU consumption) via a crafted (1) EmailField (email address) or (2) URLField (URL) that triggers a large amount of backtracking in a regular expression.

Patch / fix

  • pypi django 1.0.4, 1.1.1
  • python-django Debian 14, Debian 13, Debian 12 1.1.1-1

debian advisories DEBIAN-CVE-2009-3695

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-3695 updated

Django's forms DOS in 1.1/1.0

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.79% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi django
>=1.0, <1.0.4
>=1.1, <1.1.1
1.0.4
1.1.1

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity
  • CWE-400 Uncontrolled Resource Consumption
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.