CVE-2026-27205 SUSE CVE security@suse.de SUSE Security Team SUSE CVE-2026-27205 Interim 1 1 2026-03-05T00:15:16Z current 2026-03-05T00:15:16Z 2026-03-05T00:15:16Z cve-database/bin/generate-cvrf-cve.pl 2020-12-27T01:00:00Z CVE-2026-27205 Flask is a web server gateway interface (WSGI) web application framework. In versions 3.1.2 and below, when the session object is accessed, Flask should set the Vary: Cookie header., resulting in a Use of Cache Containing Sensitive Information vulnerability. The logic instructs caches not to cache the response, as it may contain information specific to a logged in user. This is handled in most cases, but some forms of access such as the Python in operator were overlooked. The severity and risk depend on the application being hosted behind a caching proxy that doesn't ignore responses with cookies, not setting a Cache-Control header to mark pages as private or non-cacheable, and accessing the session in a way that only touches keys without reading values or mutating the session. The issue has been fixed in version 3.1.3. The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). https://www.suse.com/support/security/rating/ SUSE Security Ratings SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Server 15 SP1-LTSS SUSE Linux Enterprise Server 15 SP2-LTSS SUSE Linux Enterprise Server 15 SP3-LTSS SUSE Linux Enterprise Server 15 SP4-LTSS SUSE Linux Enterprise Server 15 SP4-TERADATA SUSE Linux Enterprise Server 15 SP5-LTSS SUSE Linux Enterprise Server 15 SP6-LTSS SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Server 16.0 SUSE Linux Enterprise Server Teradata 15 SP4 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Module for Public Cloud 12 SUSE Linux Enterprise Server for SAP Applications 15 SP4 SUSE Linux Enterprise Server for SAP Applications 15 SP5 SUSE Linux Enterprise Server for SAP Applications 15 SP6 SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Server for SAP applications 16.0 openSUSE Leap 15.6 openSUSE Tumbleweed python-Flask python3-Flask python311-Flask python311-Flask-2.3.2-150400.3.9.1 python311-Flask-3.1.3-1.1 python311-Flask-doc python311-Flask-doc-2.3.2-150400.3.9.1 python311-Flask-doc-3.1.3-1.1 python312-Flask-3.1.3-1.1 python312-Flask-doc-3.1.3-1.1 python313-Flask python313-Flask-3.1.3-1.1 python313-Flask-doc python313-Flask-doc-3.1.3-1.1 python311-Flask-3.1.3-1.1 as a component of openSUSE Tumbleweed python311-Flask-doc-3.1.3-1.1 as a component of openSUSE Tumbleweed python312-Flask-3.1.3-1.1 as a component of openSUSE Tumbleweed python312-Flask-doc-3.1.3-1.1 as a component of openSUSE Tumbleweed python313-Flask-3.1.3-1.1 as a component of openSUSE Tumbleweed python313-Flask-doc-3.1.3-1.1 as a component of openSUSE Tumbleweed python311-Flask-2.3.2-150400.3.9.1 as a component of SUSE Linux Enterprise Module for Python 3 15 SP7 python311-Flask-2.3.2-150400.3.9.1 as a component of SUSE Linux Enterprise Server 15 SP4-TERADATA python311-Flask-2.3.2-150400.3.9.1 as a component of openSUSE Leap 15.6 python311-Flask-doc-2.3.2-150400.3.9.1 as a component of openSUSE Leap 15.6 python311-Flask as a component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS python-Flask as a component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS python311-Flask as a component of SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS python-Flask as a component of SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS python-Flask as a component of SUSE Linux Enterprise Module for Public Cloud 12 python3-Flask as a component of SUSE Linux Enterprise Module for Public Cloud 12 python311-Flask as a component of SUSE Linux Enterprise Module for Python 3 15 SP7 python-Flask as a component of SUSE Linux Enterprise Module for Python 3 15 SP7 python3-Flask as a component of SUSE Linux Enterprise Server 15 SP1-LTSS python-Flask as a component of SUSE Linux Enterprise Server 15 SP1-LTSS python3-Flask as a component of SUSE Linux Enterprise Server 15 SP2-LTSS python-Flask as a component of SUSE Linux Enterprise Server 15 SP2-LTSS python3-Flask as a component of SUSE Linux Enterprise Server 15 SP3-LTSS python-Flask as a component of SUSE Linux Enterprise Server 15 SP3-LTSS python311-Flask as a component of SUSE Linux Enterprise Server 15 SP4-LTSS python-Flask as a component of SUSE Linux Enterprise Server 15 SP4-LTSS python311-Flask as a component of SUSE Linux Enterprise Server 15 SP5-LTSS python-Flask as a component of SUSE Linux Enterprise Server 15 SP5-LTSS python311-Flask as a component of SUSE Linux Enterprise Server 15 SP6-LTSS python-Flask as a component of SUSE Linux Enterprise Server 15 SP6-LTSS python313-Flask as a component of SUSE Linux Enterprise Server 16.0 python313-Flask-doc as a component of SUSE Linux Enterprise Server 16.0 python-Flask as a component of SUSE Linux Enterprise Server 16.0 python-Flask as a component of SUSE Linux Enterprise Server Teradata 15 SP4 python311-Flask as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP4 python-Flask as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP4 python311-Flask as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP5 python-Flask as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP5 python311-Flask as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP6 python-Flask as a component of SUSE Linux Enterprise Server for SAP Applications 15 SP6 python313-Flask as a component of SUSE Linux Enterprise Server for SAP applications 16.0 python313-Flask-doc as a component of SUSE Linux Enterprise Server for SAP applications 16.0 python-Flask as a component of SUSE Linux Enterprise Server for SAP applications 16.0 python311-Flask as a component of openSUSE Leap 15.6 python311-Flask-doc as a component of openSUSE Leap 15.6 python-Flask as a component of openSUSE Leap 15.6 Flask is a web server gateway interface (WSGI) web application framework. In versions 3.1.2 and below, when the session object is accessed, Flask should set the Vary: Cookie header., resulting in a Use of Cache Containing Sensitive Information vulnerability. The logic instructs caches not to cache the response, as it may contain information specific to a logged in user. This is handled in most cases, but some forms of access such as the Python in operator were overlooked. The severity and risk depend on the application being hosted behind a caching proxy that doesn't ignore responses with cookies, not setting a Cache-Control header to mark pages as private or non-cacheable, and accessing the session in a way that only touches keys without reading values or mutating the session. The issue has been fixed in version 3.1.3. CVE-2026-27205 openSUSE Tumbleweed:python311-Flask-3.1.3-1.1 openSUSE Tumbleweed:python311-Flask-doc-3.1.3-1.1 openSUSE Tumbleweed:python312-Flask-3.1.3-1.1 openSUSE Tumbleweed:python312-Flask-doc-3.1.3-1.1 openSUSE Tumbleweed:python313-Flask-3.1.3-1.1 openSUSE Tumbleweed:python313-Flask-doc-3.1.3-1.1 SUSE Linux Enterprise Module for Python 3 15 SP7:python311-Flask-2.3.2-150400.3.9.1 SUSE Linux Enterprise Server 15 SP4-TERADATA:python311-Flask-2.3.2-150400.3.9.1 openSUSE Leap 15.6:python311-Flask-2.3.2-150400.3.9.1 openSUSE Leap 15.6:python311-Flask-doc-2.3.2-150400.3.9.1 moderate 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N