HIGHCVSS 7.5Vulnerability
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.
Properties
- summary
- Tornado: Urlencoded body parsing omits max_num_fields, so one request can stall the event loop
- severity
- HIGH
- epss_score
- 0.00346
- cvss_severity
- HIGH
- cvss_score
- 7.5
- retrieved_at
- 2026-10-17T02:41:43+00:00
- ghsa_published
- 2026-09-02T14:38:43Z
- source_url
- https://github.com/advisories/GHSA-mpf4-983q-p7j4
- ghsa_updated
- 2026-09-02T14:38:43Z
- ghsa_id
- GHSA-mpf4-983q-p7j4
- score
- 7.5
- last_source
- FIRST EPSS
- cve_id
- CVE-2026-82397
- cvss_vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- signal_observed_at
- 2026-09-11T17:55:57+00:00
- is_ghsa_only
- false
- vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- published_at
- 2026-08-31T22:17:22.920
- last_modified
- 2026-09-09T21:09:13.080
- epss_percentile
- 0.26549
Related Entities (7)
DESCRIBED_BY (1)
→[Source]NVD
ENRICHED_BY (1)
→[Source]FIRST EPSS
REPORTED_BY (1)
→[Source]GitHub Advisory Database
VULNERABLE_TO (1)
←[Software]pip/tornado
AFFECTS (1)
→[Software]pip/tornado
HAS_WEAKNESS (2)
→[Weakness]Uncontrolled Resource Consumption
→[Weakness]Improper Validation of Specified Quantity in Input
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