CVE-2026-39847 — emmett
CRITICALCVE-2026-39847 is a critical-severity (CVSS 9.1) Path Traversal vulnerability in emmett. A fix is available for emmett — see the affected versions and patch details below.
Emmett has a path traversal in internal assets handler
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-39847.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
emmettReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | emmett | ≥ 2.5.0&&< 2.8.1 | 2.8.1pip install --upgrade 'emmett==2.8.1' |
Affected Products
emmettemmettDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for emmett, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update emmett to 2.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39847 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2026-39847 in your dependencies?
Find it across PyPI, including transitive dependencies.