GHSA-7h4p-27mh-hmrw BIT-django-2023-41164 CVE-2023-41164 PYSEC-2023-225

Django Denial of service vulnerability in django.utils.encoding.uri_to_iri

High PyPI

Severity: 0.0 / 10; High · CVSS 4.0
Exploit chance (EPSS): 1.52%; Chance of exploitation in the next 30 days. Higher than 74.58% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-1284 Improper Validation of Specified Quantity in Input; CWE-400 Uncontrolled Resource Consumption
Fix: 3.2.21; Upgrade django to this version or later

Description

In Django 3.2 before 3.2.21, 4.1 before 4.1.11, and 4.2 before 4.2.5, django.utils.encoding.uri_to_iri() is subject to a potential DoS (denial of service) attack via certain inputs with a very large number of Unicode characters.

Affected versions

PyPI

Package	Vulnerable	Fixed in
django	`>= 3.2, < 3.2.21`	`3.2.21`
django	`>= 4.1, < 4.1.11`	`4.1.11`
django	`>= 4.2, < 4.2.5`	`4.2.5`
django	`>= 3.2, < 3.2.21` `>= 4.1, < 4.1.11` `>= 4.2, < 4.2.5`	`3.2.21` `4.1.11` `4.2.5`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

django PyPI → `3.2.21`

pip

pip install --upgrade "django>=3.2.21"

poetry

poetry add "django>=3.2.21"

uv

uv add "django>=3.2.21"

Severity breakdown

CVSS 4.0 0.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Attack vector: Network
Attack complexity: Low
Attack requirements: None
Privileges required: None
User interaction: None
Confidentiality (vulnerable system): None
Integrity (vulnerable system): None
Availability (vulnerable system): Low
Confidentiality (subsequent systems): None
Integrity (subsequent systems): None
Availability (subsequent systems): None

CVSS 3.1 5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Weakness

CWE-1284: Improper Validation of Specified Quantity in Input

The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

How to prevent it

Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

CWE-400: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How to prevent it

Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
Implementation: Ensure that all failures in resource allocation place the system into a safe posture.

References

Advisories

Write-ups

djangoproject.com/weblog/2023/sep/04/security-releases

Packages

github.com/django/django

Timeline

Nov 3, 2023 Published
Jun 17, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-q238-5cxm-5c9h Django GeoDjango vulnerable to denial of service through deeply nested geometry collections	Medium	Also affects django
GHSA-wvqv-fj8w-qmhm Django GeoDjango spatial lookups allow file writes and outbound requests through GDAL raster parsing	High	Also affects django
GHSA-8qcx-xf44-272x Django: DomainNameValidator permits newline characters that may enable HTTP header injection	Medium	Also affects django
GHSA-crhf-3pfg-w68w Django: GDALRaster may over-read heap memory when constructed from bytes	Medium	Also affects django
GHSA-3h9f-r86x-qvjx Django: cache middleware may expose private responses when unrelated request cookies are present	Medium	Also affects django
GHSA-8cjm-8mp7-r2xf Django: UpdateCacheMiddleware may disclose cached responses due to case-sensitive Cache-Control handling	Medium	Also affects django
GHSA-mm6v-q8q9-pgcf Django fails to prevent reuse of a partially-initialized connection after a failed `STARTTLS` handshake	Low	Also affects django
GHSA-h7pc-vwp9-298g Django: signed cookies are vulnerable to salt namespace collisions	Medium	Also affects django

Is this in your code?

MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.

Check your repos with MergeHarbor