CVE-2026-39847
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedEmmett 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe RSGI static handler in Emmett framework versions 2.5.0 through 2.8.0 fails to sanitize path traversal sequences in URLs targeting /__emmett__ internal asset paths, allowing attackers to use '../' sequences (e.g., /__emmett__/../rsgi/handlers.py) to read arbitrary files outside the intended assets directory.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 2.5.0, < 2.8.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed Emmett versionRun `pip show emmett` or `python -c "import emmett; print(emmett.__version__)"`Affected if The installed version is 2.5.0 or higher but lower than 2.8.1
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Verify RSGI static handler is in useInspect your application configuration or main app file for RSGI-related static handler setup, particularly routes mounted under /__emmett__Affected if The RSGI static handler for internal assets (/__emmett__ paths) is enabled and mounted in your application
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Confirm /__emmett__ routes are accessibleReview your application's route definitions to confirm that internal asset paths under /__emmett__ are reachable via HTTP requestsAffected if The /__emmett__ static routes are accessible from the network
You are affected if your Emmett version is 2.5.0 or newer but older than 2.8.1 AND the RSGI static handler for /__emmett__ paths is enabled and accessible.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped2.8.1
Upgrade Emmett framework to version 2.8.1 or later, which contains the path traversal fix for the RSGI static handler.
2.8.1
- Check the currently installed Emmett version using 'pip show Emmett' or within your project's dependencies
- Upgrade to version 2.8.1 or later using 'pip install --upgrade "Emmett>=2.8.1"'
- Verify the upgrade was successful by running 'pip show Emmett' and confirming the version is 2.8.1 or higher
- Test the application to ensure it functions correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-39847 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-39847 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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