Summary
Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-82397: Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parse_qs in tornado/escape.py without passing max_num_fields. RequestHandler._execute in tornado/web.py parses the body before handler dispatch through HTTPServerRequest._parse_body and parse_body_arguments in tornado/httputil.py, so an unauthenticated request body containing millions of separator-delimited fields can synchronously stall the single-threaded event loop and delay every connection. The body is bounded only by max_buffer_size, which defaults to 104857600 bytes. This issue is fixed in version 6.5.8.
Fixed packages 3
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2 | python-tornado | 0:4.2.1-3.amzn2.0.7 |
| Amazon Linux · 2 | python-tornado-debuginfo | 0:4.2.1-3.amzn2.0.7 |
| Amazon Linux · 2 | python-tornado-doc | 0:4.2.1-3.amzn2.0.7 |
Vulnerabilities 1
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High 7.5
Tornado: Urlencoded body parsing omits max_num_fields, so one request can stall the event loop
Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parse_qs in tornado/escape.py without passing max_num_fields. RequestHandler._execute in t…
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-82397.html