CVE intelligence and bounded remediation

CVE-2026-39847 — Emmett is a full-stack Python web framework designed with simplicity

Critical CVSS 9.1

Emmett is a full-stack Python web framework designed with simplicity. From 2.5.0 to before 2.8.1, the RSGI static handler for Emmett's internal assets (/__emmett__ paths) is vulnerable to path traversal attacks. An attacker can use ../ sequences (eg /__emmett__/../rsgi/handlers.py) to read arbitrary files outside the assets directory. This vulnerability is fixed in 2.8.1.

Severity
Critical
CVSS
9.1 (3.1)
Published
2026-04-07
CISA KEV
Not currently listed
Ecosystem
python/pypi
Weaknesses
CWE-22

Affected products

  • emmett / emmett

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

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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