Resource exhaustion in Tornado - CVE-2026-115927
Published: November 9, 2026
Vulnerability identifier: #VU162931
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-115927
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to deny service to other connections handled by a Tornado server process.
The vulnerability exists due to Tornado's HTTP/1.1 body parser processing all available chunks without yielding to the event loop when reading chunked request bodies. An unauthenticated remote attacker can send millions of one-byte chunks to a handler that reads the request body, blocking the process for close to a minute per request.
Affected software
Tornado
openEuler
python-tornado
python-tornado-debuginfo
python-tornado-debugsource
python3-tornado
python-tornado-help
openEuler
python-tornado
python-tornado-debuginfo
python-tornado-debugsource
python3-tornado
python-tornado-help
How to mitigate CVE-2026-115927
Install security update from vendor's website.
Tornado - update to 6.6.0
python-tornado - update to 6.6-1
python-tornado-debuginfo - update to 6.6-1
python-tornado-debugsource - update to 6.6-1
python3-tornado - update to 6.6-1
python-tornado-help - update to 6.6-1
python-tornado - update to 6.6-1
python-tornado-debuginfo - update to 6.6-1
python-tornado-debugsource - update to 6.6-1
python3-tornado - update to 6.6-1
python-tornado-help - update to 6.6-1