Information disclosure in Tornado - CVE-2026-49853

Vulnerability identifier: #VU149936

CSH Severity: Low

CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-49853

CWE-ID: CWE-200

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to disclose credentials intended for one origin to a different origin.

The vulnerability exists due to improper handling of authorization headers in SimpleAsyncHTTPClient when following cross-origin 3xx redirects. A remote user can cause the client to forward authorization credentials to a different origin.

Redirect following is enabled by default.

Tornado
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Desktop 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Enterprise Micro
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
SUSE Manager Client Tools for SLE
SUSE Linux Enterprise Server for the Raspberry Pi
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP Applications
SUSE Linux Enterprise Desktop
Python 3 Module
Basesystem Module
openSUSE Leap
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
python3-tornado
python-tornado
python-tornado-debuginfo
python-tornado-debugsource
python3-tornado-debuginfo
python311-tornado6
python311-tornado6-debuginfo
python-tornado6-debugsource
python-tornado (Red Hat package)
python-tornado-help

Install security update from vendor's website.

Tornado - update to 6.5.6
python3-tornado - addressed in versions 4.2.1-17.21.1, 4.5.3-150000.3.22.1
python-tornado - update to 4.2.1-17.21.1
python-tornado-debuginfo - addressed in versions 4.2.1-17.21.1, 4.5.3-150000.3.22.1
python-tornado-debugsource - addressed in versions 4.2.1-17.21.1, 4.5.3-150000.3.22.1
python3-tornado-debuginfo - update to 4.5.3-150000.3.22.1
python311-tornado6 - update to 6.3.2-150400.9.18.1
python311-tornado6-debuginfo - update to 6.3.2-150400.9.18.1
python-tornado6-debugsource - update to 6.3.2-150400.9.18.1
python-tornado (Red Hat package) - addressed in versions 6.4.2-1.el9_4.3, 6.5.8-0.el9_8.1, 6.5.8-0.el10_0.1
python3-tornado - update to 6.5-5
python-tornado-help - update to 6.5-5
python-tornado-debugsource - update to 6.5-5
python-tornado-debuginfo - update to 6.5-5
python-tornado - update to 6.5-5

• https://github.com/tornadoweb/tornado/security/advisories/GHSA-3x9g-8vmp-wqvf

• Multiple vulnerabilities in Tornado
• openEuler 24.03 LTS SP3 update for python-tornado
• openEuler 24.03 LTS SP1 update for python-tornado
• SUSE update for python-tornado6
• SUSE update for python-tornado
• SUSE update for python-tornado
• Red Hat Enterprise Linux 9 update for python-tornado
• Red Hat Enterprise Linux 10 update for python-tornado
• Red Hat Enterprise Linux 9 update for python-tornado