RCE in Encode Uvicorn
CVE-2020-7694
This affects all versions of package uvicorn. The request logger provided by the package is vulnerable to ASNI escape sequence injection. Whenever any HTTP request is received, the default behaviour of uvicorn is to log its details to either the console or a log file. When attackers request crafted URLs with percent-encoded escape sequences, the logging component will log the URL after it's been processed with urllib.parse.unquote, therefore converting any percent-encoded characters into their single-character equivalent, which can have special meaning in terminal emulators. By requesting URLs with crafted paths, attackers can: * Pollute uvicorn's access logs, therefore jeopardising the integrity of such files. * Use ANSI sequence codes to attempt to interact with the terminal emulator that's displaying the logs (either in real time or from a file).
Vulnerability class: RCE (Remote Code Execution)
EPSS: 0.014 (68.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.
Affected products
- Encode Uvicorn
- N/a Uvicorn — versions 0
Weakness classification (CWE)
References
- report@snyk.io (Exploit, Third Party Advisory, x_refsource_MISC)
- report@snyk.io (Product, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2020-7694?
- CVE-2020-7694 is a low-severity vulnerability in Encode Uvicorn, classified under Code Injection. CVSS score: 3.7/10. Published 2020-07-27.
- How severe is CVE-2020-7694?
- Low severity. CVSS v3 base score is 3.7 out of 10.