CVE-2026-53877: Django Information Disclosure Vulnerability

CVE-2026-53877 Overview

CVE-2026-53877 is an out-of-bounds read vulnerability in the Django web framework's geospatial module. The flaw resides in django.contrib.gis.gdal.GDALRaster, which over-reads its in-memory buffer when constructed from a bytes object. Accessing the vsi_buffer property can disclose adjacent process memory or trigger a segmentation fault, degrading service availability. The issue affects Django 6.0 before 6.0.7 and Django 5.2 before 5.2.16. Earlier unsupported branches such as 5.0.x, 4.1.x, and 3.2.x were not evaluated and may also be impacted. The vulnerability is classified under [CWE-805] (Buffer Access with Incorrect Length Value).

Critical Impact
Attackers reaching code paths that expose GDALRaster.vsi_buffer on attacker-controlled bytes can leak adjacent memory contents or crash the worker process.

Affected Products

Django 6.0 through 6.0.6
Django 5.2 through 5.2.15
Earlier unsupported series (5.0.x, 4.1.x, 3.2.x) potentially affected but unevaluated

Discovery Timeline

2026-07-07 - Django project releases security fixes and credits Bence Nagy for reporting the issue
2026-07-07 - CVE-2026-53877 published to NVD
2026-07-09 - Last updated in NVD database

Technical Details for CVE-2026-53877

Vulnerability Analysis

The defect lives in Django's GIS component, specifically the GDALRaster class wrapping the GDAL raster driver. When a caller constructs a GDALRaster from a bytes object, Django stores the buffer in memory and later exposes it through the vsi_buffer property. The exposed read operation uses an incorrect length calculation, allowing it to read beyond the boundary of the original bytes allocation. The result is either disclosure of adjacent process memory or a segmentation fault that terminates the WSGI or ASGI worker. Because Django worker processes typically handle many requests, a crash translates directly into service degradation for concurrent clients.

Root Cause

The underlying weakness is [CWE-805]: Buffer Access with Incorrect Length Value. GDALRaster.vsi_buffer computes the accessible size from GDAL virtual file system metadata rather than the bounds of the Python bytes object supplied by the caller. When the metadata reports a size larger than the backing allocation, the read continues into unrelated heap memory.

Attack Vector

Exploitation requires an application code path that constructs GDALRaster from untrusted bytes and then returns, logs, or otherwise exposes vsi_buffer data. Applications that accept raster uploads, process user-supplied GIS payloads, or expose raster APIs are the primary targets. The attack vector is network-based and does not require authentication, but exploitation depends on the presence of a vulnerable code path in the target application.

No public proof-of-concept exploit code is available. Refer to the Django Weblog Security Release for authoritative technical details.

Detection Methods for CVE-2026-53877

Indicators of Compromise

Unexpected segmentation faults or worker crashes in gunicorn, uwsgi, or daphne processes handling requests that touch django.contrib.gis
Anomalous response payloads containing non-raster binary data returned from endpoints that process raster uploads
Repeated malformed raster uploads originating from a small set of source IP addresses

Detection Strategies

Inventory Django deployments and enumerate applications importing django.contrib.gis.gdal.GDALRaster from request handlers
Review application logs for SIGSEGV signals or abrupt worker restarts correlated with GIS endpoints
Instrument request logging to capture payload sizes and content types on endpoints that accept raster data

Monitoring Recommendations

Alert on spikes in HTTP 500 responses or worker restart events from Django services exposing GIS functionality
Monitor for high-volume small-payload POST requests targeting known raster endpoints
Correlate crash dumps or coredumps with the versions listed in the vendor advisory

How to Mitigate CVE-2026-53877

Immediate Actions Required

Upgrade to Django 6.0.7 or Django 5.2.16 as documented in the Django Security Release Notes
Audit application code for use of GDALRaster constructed from untrusted bytes and restrict exposure of the vsi_buffer property
If running an unsupported Django branch (5.0.x, 4.1.x, 3.2.x), migrate to a supported release since backports are not provided

Patch Information

The Django project released fixed versions on 2026-07-07. Supported patched releases are Django 6.0.7 and Django 5.2.16. Details are published on the Django Weblog Security Release and announced through the Django Announcements Group.

Workarounds

Disable or gate any application endpoints that instantiate GDALRaster from user-supplied bytes until patching is complete
Validate raster payloads on ingress using an out-of-process tool such as gdalinfo before handing bytes to Django
Deploy a web application firewall rule to reject requests with raster MIME types on endpoints that do not require them

bash

# Upgrade Django to a patched release
pip install --upgrade "Django>=6.0.7,<6.1"   # for the 6.0.x series
pip install --upgrade "Django>=5.2.16,<5.3"  # for the 5.2.x series

# Verify the installed version
python -c "import django; print(django.get_version())"