Answer in brief
CVE-2026-31958 records a High severity (CVSS 7.5) vulnerability in Tornado is vulnerable to DoS due to too many multipart parts. The current sources do not mark it as known exploited. The current feed maps tornado (pip), tornado (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps tornado (pip), tornado (pypi). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| tornadopip | <=6.5.4 | 6.5.5 |
| tornadopypi | >=0 <6.5.5 | 6.5.5 |
Published upstream
Mar 12, 2026
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Jun 11, 2026
In versions of Tornado prior to 6.5.5, the only limit on the number of parts in `multipart/form-data` is the `max_body_size` setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts. Tornado 6.5.5 introduces new limits on the size and complexity of multipart bodies, including a default limit of 100 parts per request. These limits are configurable if needed; see `tornado.httputil.ParseMultipartConfig`. It is also now possible to disable `multipart/form-data` parsing entirely if it is not required for the application.
Quoted source text, attributed separately from HOL analysis.