Quick answers
- Is CVE-2026-115927 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-115927 being exploited in the wild.
- How severe is CVE-2026-115927?
- Medium severity, with a CVSS score of 5.3, published 26 October 2026.
- Which products and versions are affected?
- tornado (PyPI) < 6.6, ECOSYSTEM:introduced=0,fixed=6.6; Tornado Project Tornado before 6.6.0.
- Is there a fix for CVE-2026-115927?
- Yes. tornado (PyPI): upgrade to 6.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-115927 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-115927?
- Check whether you run tornado (PyPI) or Tornado Project Tornado at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- tornado (PyPI): upgrade to 6.6 or later
pip install "tornado>=6.6"
Technical details
Tornado's HTTP/1.1 chunked transfer encoding decoder processes body data without yielding to the event loop, allowing an unauthenticated remote attacker to send millions of one-byte chunks to monopolize CPU. Additionally, handlers lacking @stream_request_body retain each chunk as a separate object, consuming roughly 20x the received body size in memory. The vulnerability stems from insufficient event loop yields during chunk processing and chunk buffering inefficiency; it is fixed in version 6.6.0 by yielding every 256KB and coalescing small chunks.
Affected products
- Tornado Project Tornado before 6.6.0
Identifiers
- CVE-2026-115927
- GHSA-r4j5-9xpp-3985
Timeline
- 2026-10-26: disclosed
- 2026-10-07: patched