Bug 2526562 (CVE-2026-82397) - CVE-2026-82397 python-tornado: Tornado: Denial of Service via excessive URL-encoded body fields
Summary: CVE-2026-82397 python-tornado: Tornado: Denial of Service via excessive URL-e...
Keywords:
Status: NEW
Alias: CVE-2026-82397
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2542503 2542504 2547932 2547933 2547934
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-31 21:41 UTC by OSIDB Bzimport
Modified: 2026-11-11 03:11 UTC (History)
48 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:84798 0 None None None 2026-10-19 10:56:38 UTC
Red Hat Product Errata RHSA-2026:84843 0 None None None 2026-10-19 11:58:54 UTC
Red Hat Product Errata RHSA-2026:84844 0 None None None 2026-10-19 11:59:03 UTC
Red Hat Product Errata RHSA-2026:85135 0 None None None 2026-10-19 12:57:26 UTC
Red Hat Product Errata RHSA-2026:98104 0 None None None 2026-11-11 01:40:51 UTC
Red Hat Product Errata RHSA-2026:98106 0 None None None 2026-11-11 02:32:13 UTC
Red Hat Product Errata RHSA-2026:98107 0 None None None 2026-11-11 02:55:11 UTC
Red Hat Product Errata RHSA-2026:98110 0 None None None 2026-11-11 03:11:23 UTC

Description OSIDB Bzimport 2026-08-31 21:41:14 UTC 
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.
Comment 3 Jon Orris 2026-10-19 10:56:35 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:84798 https://access.redhat.com/errata/RHSA-2026:84798
Comment 4 Jon Orris 2026-10-19 11:58:51 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:84843 https://access.redhat.com/errata/RHSA-2026:84843
Comment 5 Jon Orris 2026-10-19 11:59:00 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:84844 https://access.redhat.com/errata/RHSA-2026:84844
Comment 6 Jon Orris 2026-10-19 12:57:23 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Via RHSA-2026:85135 https://access.redhat.com/errata/RHSA-2026:85135
Comment 9 errata-xmlrpc 2026-11-11 01:40:48 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:98104 https://access.redhat.com/errata/RHSA-2026:98104
Comment 10 errata-xmlrpc 2026-11-11 02:32:09 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:98106 https://access.redhat.com/errata/RHSA-2026:98106
Comment 11 errata-xmlrpc 2026-11-11 02:55:08 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:98107 https://access.redhat.com/errata/RHSA-2026:98107
Comment 12 errata-xmlrpc 2026-11-11 03:11:20 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:98110 https://access.redhat.com/errata/RHSA-2026:98110
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