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Vulnerabilities

Security fix · CVE-2026-114138

Django REST framework is a toolkit for building Web APIs.

Published Oct 21, 2026 · catalog updated Oct 22, 2026 · Django REST framework is

Last checked Nov 4, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-114138. EPSS is 0.60%. Act only if a listed version of Django REST framework is is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Django REST framework is).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.60%
Remediation
Version ranges on file
Affected products
package pip · pip djangorestframework · pypi djangorestframework

### Summary DRF's content negotiation parses each Accept token several times per request and never limits the number of tokens or their total size. Each parse ends up in Django's parse_header_parameters, which takes quadratic time when a quoted parameter value is packed with semicolons. On my machine a single GET with a 780KB Accept header made of 96 such tokens kept one gunicorn worker busy for 18.87 seconds (Django 6.1, djangorestframework 3.18.0, gunicorn 26.0.0, Python 3.13, Docker on macOS). The header is syntactically valid, fits inside gunicorn's default header limits, and needs no authentication. Two concurrent requests, which is one per sync worker, made a default two worker deployment stop answering for my whole 40 second test window. It recovered half a second after I stopped sending. ### Details #### What happens get_accept_list() splits the Accept header on commas with no cap on token count or total size, at rest_framework/negotiation.py:96-97. For every token, select_renderer() calls media_type_matches() once per renderer, and each call builds fresh _MediaType objects for both sides, at rest_framework/negotiation.py:53-56 and rest_framework/utils/mediatypes.py:22-23. calls django.utils.http.parse_header_parameters unconditionally, at rest_framework/utils/mediatypes.py:47. When nothing matches, DRF raises NotAcceptable (406). Rendering that error response also needs a renderer, so finalize_response() runs the entire negotiation a second time through perform_content_negotiation(force=True), at rest_framework/views.py:434-437. With the default two renderers this comes to about six parses per Accept token per request. I confirmed the count by instrumenting _MediaType with a counter: six per token, three from the normal pass and three from the forced re-negotiation. The quadratic part is on the Django side. parse_header_parameters splits parameters with _parseparam, which handles quoted values by recounting the quote characters from the start of the string

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • package pipversion unspecified
  • pip djangorestframework< 3.18.2
  • pypi djangorestframeworkversion unspecified

How to fix CVE-2026-114138

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-114138. EPSS is 0.60%. Act only if a listed version of Django REST framework is is installed.

Which versions are affected?

Compare what you have installed with < 3.18.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption; CWE-407. EPSS 0.60%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Django security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 21, 2026 · NIST NVD

    Detected

    Django REST framework is a toolkit for building Web APIs. Prior to 3.18.2, DefaultContentNegotiation.get_accept_list in rest_framework/negotiation.py accepts an unbounded number and aggregate size of Accept tokens, while select_renderer in that file repeatedly invokes _MediaType parsing from rest_framework/utils/mediatypes.py for each attacker-controlled token, every renderer, and forced 406 reneg

  2. Oct 22, 2026 · GitHub Advisory Database

    Updated

    ### Summary DRF's content negotiation parses each Accept token several times per request and never limits the number of tokens or their total size. Each parse ends up in Django's parse_header_parameters, which takes quadratic time when a quoted parameter value is packed with semicolons. On my machine a single GET with a 780KB Accept header made of 96 such tokens kept one gunicorn worker busy for 1

Sources

  • CVE.orgVulnerability recordCVE-2026-114138

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-114138

    30-day exploitation probability 0.60%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-33wh-fxxf-88vv

    Django REST framework: Accept header with many large quoted parameters burns ~19s of CPU per request in content negotiation

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-114138

    DRF's content negotiation parses each Accept token several times per request and never limits the number of tokens or their total size. Each parse ends up in Django's parse_header_parameters, which takes quadratic time when a quoted parameter value is packed with semicolons. On my machine a single GET with a 780KB Accept header made of 96 such tokens kept one gunicorn worker busy for 18.87 seconds

    advisories.gitlab.com
  • NIST NVDVulnerability recordCVE-2026-114138

    Django REST framework is a toolkit for building Web APIs. Prior to 3.18.2, DefaultContentNegotiation.get_accept_list in rest_framework/negotiation.py accepts an unbounded number and aggregate size of Accept tokens, while select_renderer in that file repeatedly invokes _MediaType

    nvd.nist.gov
  • Snyk Vulnerability DatabasePackage advisorySNYK-PYTHON-DJANGORESTFRAMEWORK-21431458

    Inefficient Algorithmic Complexity

    security.snyk.io

References

Freshness

Last verified in this catalog Nov 4, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 4, 2026
  • Snyk Vulnerability DatabaseOct 24, 2026
  • GitHub Advisory DatabaseOct 23, 2026
  • GitLab Advisory DatabaseOct 23, 2026
  • CVE.orgOct 22, 2026
  • NIST NVDOct 22, 2026