Description
A flaw was found in Yelp due to an overly permissive Content Security Policy (CSP) implementation provided by yelp-xsl. A malicious Flatpak application can open crafted help content through the OpenURI portal. By embedding an untrusted CSS stylesheet within a structured SVG document, attacker-controlled content can bypass Flatpak's intended sandbox isolation, allowing Yelp to evaluate local XML inclusions and disclose arbitrary user-readable host files through remote CSS resource requests. This may result in the unauthorized disclosure of sensitive information.
CVSS breakdown
CVSS 3.1
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Affected products
- GNOME / yelp49.1
- RedHat / enterprise_linux6.0 – 6.0
- RedHat / enterprise_linux7.0 – 7.0
- RedHat / enterprise_linux8.0 – 8.0
- RedHat / enterprise_linux9.0 – 9.0
References
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:47177
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:47178
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:54539
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:54540
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:54605
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:54624
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:54637
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:54666
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2026:57417
- VENDOR_ADVISORYhttps://access.redhat.com/security/cve/CVE-2026-13601
- MISChttps://blogs.gnome.org/mcatanzaro/2026/05/11/flatpak-sandbox-escape-via-yelp/
- MISChttps://bugzilla.redhat.com/show_bug.cgi?id=2494110
- MISChttps://gitlab.gnome.org/GNOME/yelp/-/commit/c8c8244c8a812860782d635890c9b6c43ecc2639
- MISChttps://gitlab.gnome.org/GNOME/yelp/-/work_items/238
Updated 14m ago · 8 sources