CVE intelligence and bounded remediation
CVE-2026-42196 — django-s3file is a lightweight file upload input for Django and Amazon S3
django-s3file is a lightweight file upload input for Django and Amazon S3. Prior to 7.0.2, S3FileMiddleware is vulnerable to relative path traversal attacks, where an attacker can use a modified request to escape pre-signed upload locations and have the Django application load files from random locations into request.FILES. Depending on how files are handled, this may lead to confidentiality and integrity issues. This vulnerability is fixed in 7.0.2.
- Severity
- Critical
- CVSS
- 9.9 (4.0)
- Published
- 2026-05-12
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-22, CWE-26
Affected products
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Matched remediation archetype
Path traversal, unsafe upload, and file handling
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Check exposure
- Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
- Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
- Review canonicalization and containment checks across supported operating systems and storage backends.
Remediate safely
- Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
- Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
- Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.
Authoritative sources
Complete CVE record and remediation plan
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