CVE-2025-14550: 
Django vulnerability analysis and mitigation

CVE-2025-14550 is a denial-of-service vulnerability in Django's ASGIRequest handler that allows a remote, unauthenticated attacker to exhaust server resources by sending crafted HTTP requests containing multiple duplicate headers. It affects Django versions 6.0 before 6.0.2, 5.2 before 5.2.11, and 4.2 before 4.2.28; earlier unsupported series (5.0.x, 4.1.x, 3.2.x) were not formally evaluated but may also be affected. The vulnerability was reported by Jiyong Yang and disclosed on February 3, 2026. It carries a CVSS v3.1 base score of 7.5 (High) and a CVSS v4.0 base score of 2.7 (Low) (GitHub Advisory, Django Blog).

The root cause is classified under CWE-407 (Inefficient Algorithmic Complexity) and CWE-167 (Improper Handling of Additional Special Element). Django's ASGIRequest class does not efficiently handle HTTP requests that contain a large number of duplicate headers; processing such requests triggers worst-case algorithmic behavior that consumes disproportionate CPU or memory resources. The attack requires no authentication, no user interaction, and is reachable over the network with low complexity, making it trivially exploitable against any publicly accessible Django ASGI application. The fix is tracked in the Django source repository at commit eb22e1d (GitHub Advisory, Django Changeset).

Successful exploitation causes a denial-of-service condition against the affected Django ASGI application, degrading or completely interrupting service availability. There is no impact on confidentiality or data integrity — the vulnerability is limited to availability. Applications deployed using WSGI (rather than ASGI) are not affected by this specific issue, limiting the scope to ASGI-based deployments (GitHub Advisory, Django Blog).

No public proof-of-concept exploit code or in-the-wild exploitation has been reported for CVE-2025-14550. The EPSS score is approximately 0.041% (22nd percentile), indicating a low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Detection plugins are available from Nessus (IDs: 297743, 298044, 298350, 300515, 300516, 300641, 301388, 303901, 303903) and Qualys (IDs: 6031874, 6047774, 296136) (GitHub Advisory).

1. Reconnaissance: Identify internet-facing Django applications running in ASGI mode (e.g., via Daphne, Uvicorn, or Hypercorn) on versions prior to 4.2.28, 5.2.11, or 6.0.2 using tools like Shodan or Censys, or by inspecting HTTP response headers for Django version indicators.
2. Craft malicious request: Construct an HTTP request containing a large number of duplicate headers (e.g., hundreds of repeated X-Custom-Header: value entries) targeting any accessible endpoint of the ASGI application.
3. Send the request: Transmit the crafted request to the target server. No authentication or special privileges are required.
4. Trigger resource exhaustion: The ASGIRequest handler processes the duplicate headers with inefficient algorithmic complexity, consuming excessive CPU or memory and causing the application to become unresponsive or crash, resulting in a denial-of-service condition.
5. Sustain the attack: Repeat requests in rapid succession to maintain the DoS condition and prevent service recovery (GitHub Advisory, Django Blog).

• Network: Unusual volume of HTTP requests with abnormally large or numerous headers targeting ASGI Django endpoints; requests with hundreds of repeated identical header names from a single or rotating source IP.
• Logs: Django/ASGI server logs showing repeated requests with excessive header counts; elevated request processing times or timeouts logged by the ASGI server (Daphne, Uvicorn, Hypercorn).
• Process: Sustained high CPU or memory utilization by the Django ASGI worker processes without a corresponding increase in legitimate traffic; worker process crashes or restarts correlated with specific request patterns.

Django has released patched versions 4.2.28, 5.2.11, and 6.0.2, which resolve this vulnerability. Upgrading to one of these versions is the recommended remediation. As a temporary workaround, operators can deploy a reverse proxy (e.g., nginx) in front of the ASGI application configured to limit the number or size of HTTP headers per request, reducing exposure until an upgrade is possible. Downstream vendors including Red Hat (via RHSA-2026:2694, RHSA-2026:3958, RHSA-2026:3959, RHSA-2026:5970, RHSA-2026:5971, RHSA-2026:13508), Ubuntu (USN-8009-1), Oracle Solaris, Debian, SUSE, Fedora, and Mageia have also issued patches (Django Blog, Red Hat Bugzilla, Oracle).

The Django security team published a blog post on February 3, 2026 announcing the security releases and a follow-up post on February 4, 2026 discussing recent trends observed by the security team (Django Blog, Django Security Trends). Security news outlets including SecurityOnline, GBHackers, CyberSecurityNews, and CyberPress covered the release, often grouping it with other Django vulnerabilities patched in the same release cycle. The vulnerability was also discussed on the oss-security mailing list (oss-sec). Community reaction was measured, reflecting the limited scope (ASGI-only, DoS-only) and low EPSS score.